At least two people were shot as police in riot gear blocked the main entrance to the airport and fired tear gas at the crowd, which threw rocks and bottles.
Carlos Dorestant, a 22-year-old motorcycle driver, said he saw the man next to him shot, apparently by police, as protesters dismantled a barrier near the U.N. office.
"We are asking everyone in charge to tell Jovenel to resign," he said, his shirt stained with blood. "The people are suffering."
Several protesters held up signs asking the U.S. for help. "Trump give Haiti one chance" read one, while another quoted a tweet by presidential candidate Bernie Sanders. A third referred to U.S. House Speaker Nancy Pelosi, who discussed the crisis with Haitians in Miami on Thursday.
The unrest on Friday came after almost four weeks of protests in which 17 people have been reported killed, the economy has been largely paralyzed, 2 million children have been kept from going to school and badly needed aid has been suspended, especially to rural areas. The U.S., United Nations and other important international players have yet to drop their support for Moïse, making it appear unlikely that he will step down, despite protests that have made gasoline, food and water scarce in some areas.
"We will continue until Jovenel leaves office," said Sen. Sorel Jacinthe, who was once the president's ally but joined the opposition earlier this year.
The opposition has rejected Moïse's call for dialogue and created a nine-person commission it says would oversee an orderly transition of power, with many demanding a more in-depth investigation into corruption allegations which involve the use of funds from a Venezuela-subsidized oil program. Critics say Moïse has not looked into the former top government officials accused, including ally and former President Michel Martelly.
To protest against the alleged corruption and a shortage of basic goods, Haitians have taken to the streets in force.
Opposition leader and attorney André Michel said the international community should recognize the protesters' demands and blamed Moïse for the country's economic and social problems.
"He has plunged the country into chaos," he said.
Moïse's ally, former Prime Minister Evans Paul, also met earlier this week with the Core Group, which includes officials from the United Nations, U.S., Canada and France to talk about the political situation. He has said that he believes Moïse has two options: nominate an opposition-backed prime minister or shorten the length of his mandate.
Moïse, who owned a company named in the investigation, has denied all corruption allegations. He urges dialogue and says he will not resign.
Laurent Dubois, a Haiti expert and Duke University professor, said there is no clear answer on what might happen next as the turmoil continues.
"The thing that haunts all of this is ... is this going to lead to the emergence of more authoritarian rule?" he said.
Earlier Friday, police fired tear gas at thousands gathered under a bridge to urge the international community to withdraw support for the president. Some demonstrators were carrying guns, machetes or knives.
A police commander could be heard ordering officers to take up their positions.
"It's become more than a protest!" he yelled. At various locations, water cannon trucks were on hand.
Getta Julien, 47, said she had enough of the protests and the president as she stabilized portions of rice, beans and vegetables she had packed into foam containers.
"He has to go," she said. "He's doing nothing for the country. Nothing at all."
Nearby, others cheered as Jacinthe arrived and greeted supporters, including an artist riding a white horse amid burning tires as he carried a large red and black flag that read, "Long live the economic revolution."
One protester, 38-year-old electrician Delva Sonel, said he did not want the international community to interfere.
"We're trying to send a signal to the world that we're not a little country," he said. "We want to tell them to stay out of our business."
Some questioned why international leaders had not spoken publicly against Moïse even as he and his administration face corruption allegations.
"How can they support this government if it represents everything that is wrong?" said Israel Voltaire, a 35-year-old attorney. "With us being a democratic country, it's like we're losing the war."