Four Japanese nationals have been arrested in Mae Sot district of Tak province after illegally crossing the Thailand-Myanmar border to Myawaddy, police said on Saturday.

Police said the Japanese suspects travelled by van into Mae Sot, where they checked into a hotel on Jan 31. They checked out on Feb 1, took a taxi to the Rim Moei Market, near the 1st Thai-Myanmar Friendship Bridge, and walked around like other tourists before disappearing.

At 11am the same day, police spotted a Myanmar national arriving from Myawaddy to Thailand via the bridge. The individual picked up the luggage belonging to the Japanese men from the hotel and returned to Myanmar without passing through Thai customs.

Authorities determined that the Japanese men had illegally crossed the border and were likely involved in transnational crimes or a call centre scam gang targeting Japanese people.

Police contacted the Japanese Embassy, which confirmed the four had criminal records and multiple arrest warrants for drug-related offences in Japan. When the individuals crossed back into Thailand on Friday, they were immediately arrested, and their tourist visas were revoked, police said.