A South Korean coastguard has been stabbed to death by a Chinese fisherman on Monday, a South Korean official said, according to Reuters. Another South Korean coastguard is reportedly injured.

The South Korean coastguards were confronting Chinese fishermen suspected of illegally fishing in South Korean waters, according to the South Korea official.

When the coast guard boarded the Chinese ship, the captain of that ship reportedly attacked with an unidentified weapon, striking one officer on the side and one officer in the abdomen, according to NPR. The officer who was stabbed on the side later died in the hospital.

CNN, citing Yonhap News Agency, said the weapon was a piece of broken glass.

The captain, along with eight other Chinese fishermen, has been taken into South Korean custody.  

South Korean government officials have called the Chinese ambassador to protest, reported CNN.

A Chinese government spokesperson said “China is ready to work closely with the (South Korean) side to handle the case properly.” The spokesperson also said China hopes South Korea will treat the Chinese detainees humanely.

Clashes between South Korean coast guards and Chinese fishing boats have intensified recently as Chinese fishing boats have inched closer to South Korean waters.

The Chinese have depleted local waters due to overfishing and pollution, according to the The Telegraph. Chinese fishermen, therefore, have been forced to stray further from home to land their catches.

These fishermen often resist law enforcement authorities from other countries because they want to avoid arrest and expensive fines, according to the New York Times.

Recently, Chinese fishermen have reportedly wielded weapons like axes and steel pipes, according to the New York Times.

Back in October, a clash between South Korean coast guards and Chinese fishermen had the Chinese wielding clubs and shovels and the South Korean side resorting to tear gas and rubber bullets, according to BBC.