Malaysia said on Thursday that it had summoned the Chinese ambassador to register its concerns over what the government said was an encroachment by a large number of Chinese-flagged boats in the South China Sea.
About 100 Chinese fishing boats were detected encroaching in Malaysia's waters, Malaysia's state news agency and a coastguard official said last week.
The Malaysian foreign minister confirmed that a large number of Chinese-flagged fishing boats were sighted in Malaysian waters, and the boats were accompanied by Chinese Coast Guard vessel.
Malaysia had summoned the ambassador "to seek clarification as well as to register Malaysia's concerns over the matter", a foreign ministry statement said.
China claims most of the South China Sea through which about $5 trillion in ship-borne trade passes every year. Its Southeast Asian neighbors Brunei, Malaysia, the Philippines and Vietnam, also claim parts, as does Taiwan.