Image caption The Chinese captain reportedly stabbed the coast guards with a shard of glass

The captain of a Chinese fishing boat has stabbed two South Korean coast guards, killing one and injuring another, officials say.

The clash took place after the boat was stopped for illegal fishing in the Yellow Sea off Korea's Incheon port.

Korean officials seized the vessel and detained nine Chinese crewmen.

A Chinese foreign ministry spokesman said Beijing was trying to clarify details and was willing to work closely with the South Koreans.

Chinese crews are regularly caught fishing in Korean waters. They are usually released after paying a fine.

About 430 Chinese ships have been seized for illegal fishing in the Yellow Sea so far this year, up from 370 last year, according to the coast guard.

Shards of glass

In this incident, the coast guard were able to restrain eight of the Chinese crew members but it was the captain who put up a fight, investigators said.

Media playback is unsupported on your device Media caption Ahn Sung-shik, South Korean coast guard: "The captain of the boat stabbed two coastguard officers"

"The captain of the boat who was in the steering house stabbed two of our coast guard officers with an unidentified weapon," Ahn Sung-Shik, head of the Incheon coast guard investigation department told the AP news agency.

South Korean news reports say that the fishing captain was wielding shards of glass from a broken window when coast guards raided the boat.

South Korea's foreign ministry summoned the Chinese ambassador in Seoul and lodged a protest over the clash. Korean officials have previously pressured Beijing to do more to curb illegal fishing in Korean waters.

But previous attempts to intercept Chinese fishing boats have also ended in violence.

In October the coast guard said it had used tear gas and rubber bullets to subdue Chinese fishermen wielding clubs and shovels.

There have also been a number of incidents involving Chinese sailors and the authorities of other countries.

Last month, the crew of a Chinese fishing boat was briefly detained by Japan for entering its coastal waters.

Similar arrests last year in disputed waters sparked a major diplomatic confrontation between Japan and China.

And in the South China Sea, Chinese vessels have several times angered the authorities of other countries with apparent incursions.

The sea inside South Korea's exclusive economic zone, between China and the West coast of the Korean peninsula is rich in crabs and anchovies.

The BBC's Lucy Williamson in Seoul say that illegal fishing has boomed there over the past year.