China on Friday said it "restricted" Filipino ships near the disputed islands in the South China Sea.
China Coast Guard (CCG) said it "warned, monitored and restricted two repair ships and two coast guard ships from the Philippines that trespassed China's territorial waters near Ren'ai Jiao."
The Chinese refer to the Second Thomas Shoal as Ren'ai Jiao, also known as Ayungin Shoal, which it says is part of the Nansha Islands in the disputed waters.
"China has undisputable sovereignty over the Nansha Islands including the Ren'ai Jiao as well as adjacent waters, and China firmly opposes Philippine authorities' transport of illegal building materials to its illegally 'grounded' warship," the CCG said in a statement to Chinese broadcaster CGTN.
It said CCG will "continue to carry out rights protection and law enforcement activities in waters under Chinese jurisdiction in accordance with the law."
The latest encounter between Chinese and Filipino ships comes after Manila charged Beijing with "blocking" the passage of its two vessels in the disputed South China Sea in July.
Beijing is demanding Manila remove a grounded warship from a reef in the disputed Spratly Islands. The Philippines grounded the Second World War-era warship in 1999 to reinforce the Philippines' sovereignty claims.
