MANILA • The Philippines has expressed concern about hundreds of Chinese military vessels it said were spotted this month in the disputed South China Sea, the latest example of tension in the crucial waterway.

The Philippine Coast Guard reported that some 220 vessels, believed to be manned by Chinese maritime militia, were seen moored in line formation at a reef on March 7, a cross-government task force said late last Saturday.

Yesterday, Defence Minister Delfin Lorenzana urged China to recall the vessels, saying their presence was "a clear provocative action of militarising the area".

"We call on the Chinese to stop this incursion and immediately recall these boats violating our maritime rights and encroaching into our sovereign territory," he said.

Foreign Affairs Secretary Teodoro Locsin said on Twitter that a diplomatic protest was made yesterday over the presence of the boats.

The National Task Force for the West Philippine Sea expressed concern about overfishing and destruction of the marine environment, as well as risks to safety of navigation.

China's Foreign Ministry did not respond to a request for comment yesterday, and calls to the Chinese Embassy in Manila seeking comment went unanswered.

An international tribunal in 2016 invalidated Beijing's claim to 90 per cent of the South China Sea, but the Chinese government does not recognise the ruling.

In January, the Philippines protested against a new Chinese law allowing its coast guard to fire on foreign vessels, describing it as a "threat of war".

The Chinese vessels were at the Julian Felipe Reef, also known as Whitsun Reef, in Manila's exclusive economic zone, the task force said, describing the site as "a large boomerang-shaped shallow coral reef at the north-east of Pagkakaisa Banks and Reefs".

The Philippines vowed to monitor the situation and "to peacefully and proactively pursue its initiatives on environmental protection, food security and freedom of navigation" in the South China Sea.

REUTERS, BLOOMBERG