For years, Rohingya from Myanmar have boarded boats organised by smugglers in the hope of finding refuge in Southeast Asia, usually making voyages during the dry season from November to March, when the waters are calm.
A human rights group said it believed more boats carrying Rohingya were adrift at sea, with coronavirus lockdowns in Malaysia and Thailand making it harder for them to find refuge.
"They were at sea for about two months and were starving," a Bangladesh coastguard official told Reuters in a message, adding that the ship was brought to shore late on Wednesday.
The 396 survivors would be handed to the U.N refugee agency, said the official, who had initially said they would be sent to Myanmar. The official also revised the death toll to 32 from 24.
Video images showed a crowd comprised mostly of women and children, some stick-thin and unable to stand, being helped to shore. One emaciated man lay on the sand.
One refugee told a reporter the group had been turned back from Malaysia twice and a fight had broken out onboard between passengers and crew at one point.
"We understand these men, women and children were at sea for nearly two months in harrowing conditions and that many of them are extremely malnourished and dehydrated," the U.N. refugee agency UNHCR said.
"UNHCR is offering to assist the government to move these people to quarantine facilities," it added in a statement that also offered medical attention.
Media reports that the group was infected with the virus had not been substantiated, the agency said.
More than a million live in refugee camps in southern Bangladesh, the majority having been driven from homes in Myanmar after a 2017 military crackdown the army said was a response to attacks by Rohingya insurgents.
Rights groups fear virus curbs across southeast Asia could trigger a repeat of a 2015 crisis, when a crackdown by Thailand prompted smugglers to abandon their human cargo at sea on crowded, rickety boats.
Chris Lewa, director of the Arakan Project, said she believed several more boats were stranded.
"Rohingya may encounter closed borders supported by a xenophobic public narrative," she said in a message.
"Covid-19 cannot be used to deny access to territory to desperate refugees in distress. Another maritime crisis in the Andaman Sea, as in 2015, is unacceptable."
Several boats were trying to reach Malaysian shores and monitoring had been stepped up, a police official in the northwestern state of Kedah told Reuters.
A police official in southern Thailand said five boats carrying Rohingya had been spotted off the coast of Satun province late on Monday. It was not possible to independently confirm the remarks.
People were smuggled out by boat and over land, said Kyaw Hla, a Rohingya from Sittwe in Myanmar's western Rakhine state, where tens of thousands of Rohingya have been confined in camps since a bout of violence in 2012.
"Within these eight years, there has been no progress, only degradation," he said by telephone. "People can't stand it. Since we are locked up and suffocated, people try to leave, of course."
He added, "If the coronavirus breaks out here, we'll be as good as dead."