Japanese health officials and experts on a government panel acknowledged Monday that the quarantine of the virus-hit cruise ship Diamond Princess was not perfect, but defended Japan's decision to release about 1,000 passengers after 14 days.

The officials said Japanese health authorities faced tough challenges in dealing with a foreign-operated ship that required international negotiations in the absence of established rules in such a crisis.

"The ship was not designed to be a hospital. The ship was a ship," said Shigeru Omi, a former regional director for the World Health Organization. "Of course isolation was not ideal as would be expected from a hospital, so in my view although the isolation was somehow effective, to a large extent it was not perfect."

More than 690 people were sickened on the ship and three died.

Omi, a public health expert who heads the Japan Community Health Care Organization, said it was the best they could do. While some people criticized Japan for confining more than 3,700 passengers and crew on the ship in what they called a botched quarantine, he said it was not feasible to test and relocate all of them for quarantine elsewhere.

Some medical experts who helped on the ship have said the quarantine was poorly managed.

On Monday, the health ministry said a quarantine official and a government employee who helped on the ship had tested positive and were hospitalized, bringing the number of confirmed infections among government officials to six.

Japanese passengers who did not share a room with patients, tested negative and had no symptoms at the end of the 14-day quarantine period were allowed to go home on public transportation. The sight of them traveling on bullet trains and buses with other people was viewed as an alarming sign of a Japanese lack of a sense of crisis.

Omi, however, said the passengers who passed the criteria should be treated as anyone else, and those who frequent public places in the community should be deemed equally at risk. He said the ship was a condensed version of what is happening in Japanese communities.

The number of patients in the country continues to rise, and Japan is now at a critical juncture, experts say. It has about 160 cases outside the ship, including a dozen new cases reported Monday.

In their assessment of the spread of the virus in Japan, the 12-member experts panel raised concern about the growing number of cases whose timing, location and source of transmission are unknown.

At least 18 American and several Australian former passengers have tested positive after returning home. Experts said infections are also difficult to discover because COVID-19 can be transmitted during its incubation period by asymptomatic patients.

In Japan, a former passenger in her 60s who tested negative days before getting off the ship then tested positive after taking a train home. Experts said it was unfortunate but within their expectations.

There is a "small possibility" of scattered cases that will create small clusters in communities after passengers return, said Norio Ohmagari, an infectious diseases expert at the National Center for Global Health and Medicine. "So I'd like to call upon all the travelers who disembarked from the ship ... to report to the authorities as soon as possible" if they develop any symptoms, he said. "By doing that, we can prevent another cluster from happening."

Most of about 1,000 crew members remain on board the ship under quarantine. Because of the need to run the ship and serve the passengers during the original quarantine, crew members could not be properly isolated.

Malaysia's king on Monday accepted Prime Minister Mahathir Mohamad's shocking resignation but reappointed him as interim leader following the collapse of the ruling alliance in a major political upheaval less than two years after its historic election victory.

The stunning turn of events come amid plans by Mahathir's supporters in his Bersatu party to team up with opposition parties to form a new government and thwart the transition of power to his named successor, Anwar Ibrahim.

Minutes before Mahathir tendered his resignation to the palace, Bersatu said it would leave the four-party Alliance of Hope and support Mahathir as prime minister. Eleven other lawmakers, including several Cabinet ministers, announced they were quitting Anwar's party to form an independent bloc.

Bersatu later said Mahathir had also quit as party chairman. The withdrawal of more than three dozen lawmakers means the ruling alliance has lost its majority in Parliament, throwing the country into an uncertain future and sparking fears of more turmoil over how the political drama will play out.

King Sultan Abdullah Sultan Ahmad Shah, who met leaders from the new faction on Sunday and both Anwar and Mahathir on Monday, accepted Mahathir's resignation, the chief secretary to the government, Mohamad Zuki Ali, said in a statement.

Mohamad Zuki said the king also decided Mahathir should continue as interim leader until a new prime minister is chosen and a new Cabinet formed. He said the king also dissolved the Cabinet on Mahathir's advice, essentially sealing the breakup of the current government.

The king's decision helped bring some political stability to the country after the series of dizzying events unraveled Sunday with maneuvers aimed at keeping Mahathir in power and blocking Anwar from the top job. Horse trading is expected as both factions scramble to build enough support to take power.

Anwar said Monday after meeting with Mahathir and with other alliance leaders that Mahathir was not involved in the conspiracy and had quit because he didn't want to be associated with the former corrupt regime that he worked hard to oust in the 2018 polls.

"His name was used, by those within my party and outside," Anwar told reporters. Mahathir "reiterated to me what he had said earlier, that he played no part in it and he made it very clear, that in no way will he ever work with those associated with the past regime."

Anwar said he pleaded with Mahathir to stay on to jointly defeat the conspirators but he refused.

Anwar was Mahathir's deputy during Mahathir's first stint as prime minister but they fell out politically. The pair reunited in a political pact in the May 2018 election, which ousted a ruling coalition that has governed the country since independence from Britain in 1957. Tension has erupted as Mahathir refused to set a date to relinquish power despite a preelection agreement to hand over power to Anwar.

The political plot by the defectors would include an alliance with the Malay party of disgraced former leader Najib Razak, who with several of his party leaders are standing trial on corruption charges. It would also recruit a fundamentalist Islamic party that rules two states and champions Islamic laws. The two Malay parties still have strong support from ethnic Malays, who account for 60% of Malaysia's 32 million people.

The political drama came just two days after all of the parties in the now-crumbling alliance agreed that Mahathir alone should decide when he would step down after Malaysia hosts an Asia-Pacific regional meeting in November.

Mahathir has remained silent, but many Malaysians reacted with dismay and shock, saying moves to form a "backdoor" government would be unethical and that a new election should be called.

Electoral watchdog group Bersih, which has organized several protest rallies in the past, warned it would organize a mass rally if an undemocratic government is formed. Bersih and about three dozen civil society groups said democracy was in peril and demanded the defectors quit and new elections be called.

Analysts said a new "backdoor" government could give rise to Malay Islamic supremacy that would derail Malaysia's multi-ethnic society.

"If the new government goes through, Malaysia is heading toward a very regressive stage whereby racial supremacy and religious extremism would become the rule of the day," said Oh Ei Sun, a senior fellow at the Singapore Institute of International Affairs.

Two school children were among eight people injured by shrapnel from a roadside bomb near a park in Thailand's restive southern province of Songkhla on Monday.

Among the injured were a district assistant chief, a defense volunteer and villagers.

The Thai Army's Region 4 Forward Command said it believed that southern insurgents detonated the device when a converted pickup truck passed the spot. The explosion blew the vehicle off the road.

The explosion came after Sunday night's clash between the Thai Army and a group of insurgents. Five suspected southern insurgents were shot dead by security forces on a mountain in Narathiwat Province.

After the clash, Col. Pramote Prom-in, spokesman of the army's southern command, warned of possible imminent retaliation from insurgent groups.

The separatist insurgency in Thailand's largely ethnic Malay-Muslim provinces of Yala, Pattani and Narathiwat has killed nearly 7,000 people since 2004.

The Thai government is in negotiation with several insurgent groups for peace talks.

A bus on Sunday flipped after sliding backwards while it was ascending a steep hill in Thailand's southern province of Nakhon Si Thammarat, killing two passengers and injuring 18 others.

A police officer said the accident occurred when the was taking a number of tourists from the Hainan Association back to Songkhla province after a trip to Surat Thani for a Hainanese function.

The bus driver, who was slightly injured, told police that his passengers asked him to drive up a hill called Noen Thewada, a well-known tourist spot, for sightseeing.

However, when ascending toward the hill, the bus driver noticed that his vehicle was not powerful enough to advance uphill, therefore the bus started to slide backwards and then gathered speed.

The driver said the bus veered off the road, hit a tree and flipped, hence the casualties.

Two female passengers were crushed to death. Eighteen other passengers were injured, three of them seriously. They were rushed to nearby hospitals.

Police had already held the driver and will question the latter to determine the exact cause of the accident.

The death toll from a flash flood in Indonesia's Yogyakarta province has increased to seven with 23 others injured, a disaster agency official said on Saturday.

The victims were swept away by the flood as 249 students of the SMP Negeri I Turi secondary school were exploring the Sembor River in Sleman district as a boy scouting activity, spokesman of the National Disaster Management Agency Agus Wibowo said.

The spokesman said that three other students remained missing.

The accident occurred when volume of water from the upstream was suddenly rising with a strong current, sweeping away the students who were on the side of the river, Wibowo told Xinhua.

The search and rescue operation involved military personnel, policemen, rescuers from the search and rescue office, and personnel of the disaster agency as well as volunteers, according to the spokesman.