The United Nations called Saturday for nations to rescue hundreds of Rohingya it said were trapped onboard two unseaworthy vessels adrift in the Andaman Sea.

The United Nations refugee agency addressed its call to nearby countries that can swiftly deploy rescuers as hundreds of Rohingya are at risk of perishing.

The two overcrowded boats carrying about 400 passengers had experienced engine failures, and people were now "drifting in unseaworthy vessels in the Andaman Sea," the agency said, citing "various sources."

Food and water may be running out, it said, adding "there is a significant risk of fatalities in the coming days" if people are not rescued and disembarked to safety."

The vessels' precise location is unknown and it is unclear when, or exactly from where, they departed.

The UN High Commissioner for Refugees' call comes during a spike in journeys to Indonesia's westernmost province of Aceh — a voyage of about 1,800 kilometers from Bangladesh — with more than 1,000 arrivals in the biggest such wave since the 2017 crackdown.

More than 3,500 Rohingya are believed to have attempted risky journeys to Southeast Asian countries in 2022, according to UNHCR.

Nearly 350 Rohingya died or went missing last year while attempting hazardous sea crossings, the agency has estimated.

Thousands of the mostly Muslim Rohingya, heavily persecuted in Buddhist-majority Myanmar, risk their lives each year in long, expensive sea journeys — often in boats in poor condition — trying to reach Malaysia or Indonesia.

Refugee camps in Bangladesh are home to about one million Rohingya, many of whom fled neighboring Myanmar after a 2017 military crackdown.

But the conditions of the overcrowded camps have forced many to flee again.