Hundreds more of the mostly Muslim refugees from Myanmar were trapped on board another two unseaworthy vessels adrift in the Andaman Sea, the office of the United Nations High Commission for Refugees (UNHCR) said on Saturday.

The latest arrivals reached land after more than 1,000 Rohingya refugees landed in Aceh province last month, the biggest wave of Rohingya to reach Indonesia since 2015.

The latest group of Rohingya landed on Le Meulee beach on the island of Sabang before dawn on Saturday, said Miftah Cut Ade, chief of the fishing community in Aceh.

“They are mostly women and children, and they are in a weak condition,” he said.

Indonesia is not a signatory to the 1951 UN Convention on Refugees but has a history of taking in refugees when they arrive on the country’s shores.

Nearly a million Rohingya live in refugee camps in Cox’s Bazar near Bangladesh’s border with Myanmar, most after fleeing a military-led crackdown in Myanmar in 2017.

Thousands of them risk their lives each year on long and expensive sea journeys, often in flimsy boats that sail from Bangladesh, to try to reach Malaysia or Indonesia.

A 19-year-old Rohingya who gave his name as Deluarsah said the group left Bangladesh in early November and spent more than 20 days at sea in dangerous conditions.

“We come here with the single boat. The ocean is very dangerous,” Deluarsah said, adding that he was “happy” to have landed in Indonesia.

The UNHCR urged countries around the Andaman Sea to “swiftly deploy their full search and rescue capacities” to find the other two boats it said had suffered engine failure and were “aimlessly drifting”.

“UNHCR is concerned that food and water may be running out and there is a significant risk of fatalities in the coming days  if people are not rescued and disembarked to safety,” the agency said in a statement.