Bangladesh officials said on Monday a fishing boat carrying Rohingya Muslims to Southeast Asia did not set sail from its shores, where close to one million refugees live in congested camps.
Police in Bangladesh's southeast said they were investigating after a boat moored at a Thai island with dozens of Rohingya aboard, but were adamant their coast guard would have spotted the vessel.
"The boat didn't leave from Bangladesh," said Afrujul Haq Tutul, deputy police chief in Cox's Bazar district where the Rohingya camps are located.
"But, in light of the news, we are investigating this matter."
The boat, en route to Malaysia where there is a sizeable Rohingya community, stopped at an island off the west coast of Thailand early Sunday due to bad weather.
Thai officials said there were about 56 women, men and children on board and that the Rohingya would continue towards their destination.
Rohingya migrants attempting the boat routes south have been a rare sighting since Thai authorities clamped down on regional trafficking networks in 2015, leaving thousands of migrants abandoned in open waters or jungle camps.
Since then successive waves of violence in Myanmar have driven close to 800,000 Rohingya into southern Bangladesh, where they have joined hundreds of thousands who fled previous bouts of persecution.
Those who fled an army crackdown described by UN and US officials as ethnic cleansing arrived to find squalid camps and army blockades preventing them from leaving the immediate area in Cox's Bazar.
Bangladesh's refugee commissioner, Mohammad Abul Kalam, said local authorities had "no such information" about Rohingya trying their luck once again on the open ocean.
"We don't have any such intelligence about anyone leaving Bangladeshi shores for Malaysia by boat," he said.
A senior coast guard official said it was "impossible" that a captain would be able to evade patrols, which have been stepped up in recent months to combat drug trafficking and prevent people smuggling.
"They (boats) are not allowed to go out. It would be very hard to sneak out of our coastal patrol. I don't think these people sailed away from here," coast guard spokesman Abdullah al-Maruf said.
Many of the Rohingya ensnared in the 2015 boat crisis wound up in Muslim-majority Malaysia and Indonesia as Thailand stuck to a policy of not accepting the vessels.