A Philippine ship lightly collided with a Chinese vessel in the South China Sea on Monday, the Chinese coast guard said.

The incident occurred in waters adjacent to the Second Thomas Shoal in the Spratly Islands.

Beijing claims almost the entirety of the South China Sea. Parts of the region are disputed by Taiwan, the Philippines and several other Southeast Asian countries.

Trillions of dollars in ship-borne trade pass through the South China Sea each year and oil and gas deposits are believed to lie under its seabed.

What did the Chinese coast guard say about the collision?

The Chinese coast guard accused the Philippine ship of having "illegally broken into the sea near Ren'ai Reef in China's Nansha Islands," using Beijing's official term for the Spratly Islands.

"The Philippine replenishment ship ignored many solemn warnings from the Chinese side," Beijing's coast guard said in a statement.

It "approached the... Chinese vessel in an unprofessional way, resulting in a collision", the statement read.

"The Chinese Coast Guard took control measures against the Philippine ship in accordance with the law," it said, without elaborating further.

China implements new coast guard rules

China had previously warned the Philippines about intruding into what it considered its territorial waters and issued new rules that went into effect on June 15.

Under the new rules, China's coast guard is authorized to use lethal force against foreign ships in waters claimed by Beijing and detain trespassers without trial for 60 days.

Philippine President Ferdinand Marcos called the measures a "very worrisome" escalation.

Manila has accused the Chinese coast guard of "barbaric and inhumane behavior" against Philippine vessels.

On Friday, the G7 bloc of countries criticized what it called "dangerous" Chinese incursions in the South China Sea.