SEOUL - The People's Democratic Republic of Korea has seized a Republic of Korea fishing boat in the Sea of Japan (East Sea), the ROK's coastguard said Sunday, in an incident which could further inflame high cross-border tensions.

The boat with four ROK and three Chinese crewmen was detained while apparently operating near the DPRK's exclusive economic zone, the coastguard said in a statement. It was being towed on Sunday to the DPRK's northeastern port of Songjin.

"We urge DPRK authorities to handle this case in accordance with international norms and practices and return the ship and the crew at the earliest possible date," the coastguard said.