Two men claiming to be from North Korea were found aboard a wooden fishing boat drifting off northern Japan and have been detained, an official said on Monday.
The wooden vessel was spotted some 1.5 kilometres off Aomori prefecture in the Sea of Japan on Sunday, according to the Japanese coastguard official.
"The two men said they were from North Korea and their vessel was drifting due to engine trouble," the official said, adding the men had no identity documents and were being questioned on board their patrol boat.
Five people were originally on the boat, which departed North Korea in mid-December, and three were missing after falling into the sea in bad weather, local media reported.
Dozens of North Korean fishing vessels wash up on Japan's coast every year.
Experts say some fishermen from the North are travelling far out to sea in order to satisfy government mandates for bigger catches.
But their old and poorly equipped vessels are prone to mechanical and other problems, including running out of fuel, and there are few ways for them to call for rescue.
Boats have also washed up on Japanese shores with the crew on board dead -- referred to as "ghost ships" by local media.
Last year 10 North Koreans rescued from a tiny wooden boat drifting off northern Japan were deported back to their country, including the captain, who has been in custody on theft charges.