A migrant boat pushed back to sea by Southeast Asian nations over the weekend has not been heard from for two days, raising concerns about what has happened to the 300 people on board, rights groups said on Monday.
The boat was pushed backwards and forward between Malaysian and Thai waters last week in what the International Organization for Migration (IOM) has described as "maritime ping-pong".
It is one of many vessels adrift in the Andaman Sea after human traffickers jumped ship when a crackdown by Thailand's junta made it difficult for the criminals that prey on Bangladeshis and stateless Rohingya from western Myanmar to land on Thai shores.
The overcrowded wooden vessel was last seen late on Saturday when the Thai navy towed it away from Thailand and toward Indonesia, Thai Navy Lieutenant Commander Veerapong Nakprasit told Reuters.
"There is absolutely no information because they are out of the radar's radius," Veerapong told Reuters. "The last known location was on May 16 at 9.30 p.m. (1430 GMT)."
Chris Lewa, whose Arakan Project tracks the movement of Rohingya boats, also said there has been no word from the boat since Saturday.
"We don't have any news," she said. "It's unbearable not knowing what has happened to people on board."
The boat was first discovered foundering off the southern Thai island of Koh Lipe on Thursday, several days after Rohingya activists announced it was missing.
Thai authorities supplied food, fuel and water to the starving migrants, before pointing it back out to sea. That was the first of three occasions the Thai navy towed the boat out of Thai waters, and Reuters reporters on a speedboat saw it intercepted once by the Malaysians.
The fate of the boat has been unknown since shortly after the third time the Thais towed the boat out and sent it towards the Indonesian province of Aceh on Saturday.
An Indonesian patrol boat spotted a Rohingya boat off Aceh on Sunday, which then did not enter its waters, military spokesman Major General Mochamad Fuad Basya was quoted as saying by local news website Detik.com.
It was unclear if the boat was the one repelled from Thailand the day before. Fuad did not respond to requests from Reuters for comment.
The deputy commander of Malaysia's Maritime Police, Abdul Rahim bin Abdullah, said local authorities had been told by the Thai government the boat was in waters near Koh Lipe, but that it had not been detected by Malaysia.
Local governments had shown little concern for the fate of those on the boat, said Amy Smith, an executive director of Fortify Rights, a Southeast Asia-based watchdog group.
"They think that as soon as they get someone out of their territory it's no longer their responsibility," Smith said.
"It's scary ... Pushing boats back is really a death sentence for people."
The United Nations High Commissioner for Refugees has been among the critics of the Thai, Malaysian and Indonesian policy of not taking in the boats. Many migrants are believed to have been at sea for months, often surviving in desperate conditions.
(By Aubrey Belford; Additional reporting by Kaweewit Kaewjinda, Kanupriya Kapoor and Al-Zaquan Amer Hamzah; Editing by Simon Webb/Ruth Pitchford)