Kuala Lumpur summoned Beijing's envoy yesterday over claims that 100 Chinese vessels were fishing in Malaysia-claimed waters of the hotly disputed South China Sea over the past week.
The Foreign Ministry said yesterday it had confirmed with the local authorities reports that the boats were accompanied by Chinese coast guard vessels when they were seen off Sarawak's coast on March 24.
The ministry said in a statement that it had summoned China's Ambassador to Malaysia, Dr Huang Huikang, yesterday "to seek clarification as well as to register Malaysia's concerns over the matter".
It said it was confident that as the bilateral relationship with China has been elevated to a comprehensive strategic partnership, an "amicable resolution" would be found. But it did not specify any outcomes of the meeting with the ambassador.
While Malaysia's navy had insisted on Monday that no foreign fishing vessels were spotted in its waters in the resource-rich sea, its maritime authorities said on Tuesday it had shadowed up to 100 Chinese boats that were fishing off Sarawak from March 24 to Sunday.
The Malaysian Maritime Enforcement Agency said that the boats were found via aerial surveillance. It released photographs of the vessels, including two Chinese coast guard ships.
The confusion had stalled any action from the Foreign Ministry against the Asian superpower despite reports of the encroachment surfacing last week.
China is Malaysia's top trade partner. Its investments in Malaysia have rocketed over the past year, including billions paid to 1Malaysia Development Berhad (1MDB) - whose debt pile had been an albatross around Prime Minister Najib Razak's neck - to take control of the state investor's energy and real estate assets.
Beijing has maintained its fishermen are only operating in "traditional Chinese fishing grounds", a defence it has also offered against similar allegations from Indonesia.
Last week, Indonesia registered its protest with China over an incident involving a Chinese coast guard vessel and fishing boat off Natuna Islands in the South China Sea.
China claims most of the disputed sea. Brunei, Malaysia, the Philippines, Taiwan and Vietnam also claim parts of it.
The cases involving Malaysia and Indonesia are the latest in a series of events in the South China Sea that have raised tensions in the region.
In February, Taiwan and the US said China has deployed anti-aircraft missiles and fighter jets on Woody Island in the Paracel chain. New satellite images also appeared to show the construction of helicopter landing sites in the Paracels.
In January, an American navy destroyer sailed within 12 nautical miles of Triton Island in the Paracels, in what the US said was an effort to counter attempts to limit freedom of navigation. China's Defence Ministry called the US action "irresponsible and extremely dangerous", reported Reuters.
Meanwhile, US officials expressed concern on Wednesday that a ruling by an international tribunal in The Hague - expected in the coming weeks - on a case brought by the Philippines against China over its South China Sea claims could prompt Beijing to declare an exclusion zone in the region. It said such a move would be "destabilising".