Via Twitter, Trump expressed his support of the "brave, long-suffering people" of Iran on Saturday after hundreds gathered at universities in Tehran to protest the government's belated acknowledgement of errantly shooting down the plane, killing all 176 passengers aboard.
Secretary of State Mike Pompeo also took to Twitter to express his support for the Iranian people and lashed out against Iran's supreme leader Ayatollah Ali Khamenei and the "regime's lies, corruption, ineptitude."
The protesters demanded officials involved in the missile attack be removed from their positions and tried. Police broke up the demonstrations.
Britain has accused Iran of violating international law after its ambassador to Iran was arrested and briefly detained during protests in Tehran.
Iranian media said ambassador Rob Macaire was arrested outside a university and detained for more than an hour before being released. Protests have been taking place after the Iranian government admitted that its Revolutionary Guard shot down a Ukrainian passenger plane by mistake, killing all 176 people on board.
U.K. Foreign Secretary Dominic Raab said "the arrest of our ambassador in Tehran without grounds or explanation is a flagrant violation of international law."
"The Iranian government is at a crossroads moment," he said. "It can continue its march towards pariah status with all the political and economic isolation that entails, or take steps to de-escalate tensions and engage in a diplomatic path forwards."
Prime Minister Boris Johnson earlier called Iran's admission that it shot down the plane was "an important first step" and called for de-escalation of tensions between Iran and the United States.
Ukraine is offering over $8,000 in financial compensation to the families of its citizens who died in the jetliner crash in Iran earlier this week.
All 176 people on board the plane were killed, including 11 Ukrainians. Iranian officials have admitted responsibility for mistakenly shooting down the plane.
Ukrainian President Volodymyr Zelenskiy said in a video address Saturday that his government will also push Iran to provide separate compensation to the victims' families.
He had just spoken by phone to Iran's president, Hassan Rouhani, and said Iran promised to prosecute those responsible for the shootdown.
The Ukrainian Cabinet says each family will receive the equivalent of $8,300 from the state.
The crash happened early Wednesday, hours after Iran launched a ballistic missile attack on U.S. bases in Iraq. That attack was in retaliation for the U.S. killing of a top Iranian general.
Ukraine's president says Iran has pledged to quickly identify and return victims' remains from the jetliner that Iran accidentally shot down earlier this week.
He says Iran has also promised to prosecute any Iranian officials responsible for shooting down the Ukrainian aircraft. All 176 people on board were killed, including 11 Ukrainians.
Volodymyr Zelenskiy says he "will return all those dead to their families," adding: "All the culprits will be punished."
Zelenskiy's televised speech followed a phone call with Iran's president, Hassan Rouhani.
He thanked the U.S, Britain, Canada and others for information about the crash and their support. He says that support "undoubtedly helped" push Iran to acknowledge its responsibility for the crash.
Earlier Saturday, Rouhani and other Iranian officials admitted Tehran's responsibility for mistakenly downing the Ukrainian airliner, after days of denials.
The crash happened early Wednesday, hours after Iran launched a ballistic missile attack on two military bases housing U.S. troops in Iraq in retaliation for the U.S. killing of a top Iranian general.
German Chancellor Angela Merkel say's Iran's acknowledgement that it accidentally shot down a Ukrainian passenger jet earlier this week was a positive step.
Merkel says "it is good that those who are responsible are known ... everything has to be done now to find solution with those countries where those who are affected came from."
She says it is important that everything be done to investigate the incident, which killed "176 innocent people." She says talks are needed to discuss "what the consequences will be."
Merkel spoke to reporters Saturday after a meeting with Russian President Putin in Moscow.
The Ukrainian plane was shot down early Wednesday, hours after Iran launched a ballistic missile attack on two military bases housing U.S. troops in Iraq in retaliation for the U.S. killing of a top Iranian general. No one was hurt in the attack on the U.S. bases.
Canadian Prime Minister Justin Trudeau says his focus will be on justice for the families of those who died when Iran shot down a Ukrainian jetliner earlier this week.
Iran has taken responsibility for the shootdown, saying it was by mistake amid heightened tensions with the U.S. The crash killed all 176 people on board, including 57 Canadians.
Trudeau issued a statement Saturday saying Canada is concentrating on "closure, accountability, transparency, and justice for the families and loved ones of the victims."
Trudeau called the shootdown a national tragedy and says "all Canadians are mourning together."
He says they will continue to work with partners around the world to ensure a complete and thorough investigation. He says the Canadian government expects full cooperation from Iranian authorities.
Top officials of the Ukrainian airline whose plane was shot down in Iran are criticizing Iranian authorities for keeping their civilian airspace open amid hostilities with the U.S.
Ihor Sosnovskiy, the airline's vice president, says the decision was "absolutely irresponsible."
At a news conference Saturday, he said "When you act in war then you act however you wish. But there must be protection around ordinary people. If they are shooting somewhere from somewhere, they are obliged to close the airport."
Iran has admitted it downed the Ukraine International Airlines amid fears of a U.S. retaliation after Iran launched ballistic missiles at Iraqi bases housing U.S. forces.
Airline president Yevhen Dykhne said the Iranians gave no information of a possible threat prior to the plane's takeoff.
Sweden's prime minister says that it is demanding Iran cooperate without any restrictions in investigating the downing of a jetliner by Iranian armed forces.
Stefan Lofven said Saturday: "The fact that a plane was shot down is terrible and horrifying. To have a civil aircraft shot down — whether accidentally or not — is an act that must be condemned and Iran must take full responsibility also in relation to those affected."
A total of 10 people with Swedish citizenship and another seven residing in Scandinavian country are believed to have been aboard the ill-fated Ukrainian International Airlines flight 752 flying out of the Iranian capital.
Sweden said it would remain in close contact with the other countries which lost their citizens in the crash.
Lofven said a foreign minister-level group was formed Friday to follow up with plane's downing and its investigation. He didn't provide further details.
Germany's foreign minister has called on Iran to take the appropriate measures following what he said was the "catastrophe" of it inadvertently shooting down the Ukrainian plane near the Iranian capital.
Heiko Maas told Funke Mediengruppe media on Saturday: "It's important that Iran has brought clarity. Now it should take the appropriate measures in the further investigation of this horrible catastrophe so that something like this cannot happen again."
Maas said that, "In these hours, our thoughts are with the victims and their families in all the affected nations."
An Iranian Revolutionary Guard commander says his unit accepts "full responsibility" for the accidental shootdown of a Ukrainian passenger plane.
In an address broadcast by state TV on Saturday, Gen. Amir Ali Hajizadeh says that when he learned about the downing of the plane, which killed all 176 passengers on board, "I wished I were dead."
Iran's armed forces say they mistook the passenger plane for a hostile target in the tense aftermath of Iran's ballistic missile attack on two military bases in Iraq housing U.S. troops. That attack was retaliation for the killing of Iran's top general, Qassem Soleimani, in an American airstrike in Baghdad.
Ukraine's prime minister says Iran's admission that it unintentionally shot down a Ukrainian passenger jet near the Iranian capital isn't the end of investigating the catastrophe.
The admission "is an important step in the investigation process, which is still ongoing," Oleksiy Honcharuk said in a Facebook post on Saturday. "Our experts are continuing to work at the scene of the tragedy with the aim of a detailed investigation of the causes and the final establishment of the truth."
Iran's supreme leader has offered condolences and called for an investigation after his country's armed forces acknowledged that they accidentally shot down a Ukrainian passenger plane.
Ayatollah Ali Khamenei on Saturday expressed his "deep sympathy" to the families of the 176 victims, and called on the armed forces to "pursue probable shortcomings and guilt in the painful incident."
Iran shot down the passenger plane after it took off from Tehran, amid heightened tensions stemming from the U.S. airstrike that killed Iran's top general. The military says it mistook the plane for a hostile target after launching a ballistic missile attack on two bases housing U.S. troops in Iraq.
The head of the Ukrainian airline whose jetliner was shot down by an anti-aircraft missile in Iran says he was sure all along that that the company was not at fault.
Iran on Saturday acknowledged that it shot down the Ukraine International plane three days earlier, killing all 176 people aboard, after repeated denials from Iranian officials.
"We did not for a second doubt that our crew and our plane could not have been the cause of this terrible, awful air catastrophe," airline president Evgeniy Dikhne said on Facebook. "They were our best guys and girls. The best."
Ukraine's president says Iran must take further steps, including an official apology, following its admission that one of its missiles shot down an Ukrainian passenger plane.
President Volodymyr Zelenskiy said in a statement Saturday that Ukraine expected from Iran "assurances" of a "full and open investigation, bringing the perpetrators to justice."
He added that Ukraine expected the "paying of compensation" and "official apologies through diplomatic channels."
He also expressed hope for the continuation of the crash investigation without delay. A team of Ukrainian investigators is in Iran.
"Our 45 specialists should get full access and cooperation to establish justice," he said.
Iran announced Saturday that its military "unintentionally" shot down a Ukrainian jetliner, killing all 176 aboard.
The statement came Saturday morning and blamed "human error" for the shootdown.
The jetliner, a Boeing 737 operated by Ukrainian International Airlines, went down on the outskirts of Tehran during takeoff just hours after Iran launched a barrage of missiles at U.S. forces.
Iran had denied for several days that a missile downed the aircraft. But then the U.S. and Canada, citing intelligence, said they believe Iran shot down the aircraft.
The plane, en route to the Ukrainian capital of Kyiv, was carrying 167 passengers and nine crew members from several countries, including 82 Iranians, at least 63 Canadians and 11 Ukrainians, according to officials.