BEIJING - China strongly protested a bill signed into law in the Philippines Wednesday that lays claim to parts of the disputed Spratly Islands in the South China Seas, state press said.

"The Chinese government expresses its strong dissatisfaction and stern protest over the adoption of the bill that violated China's sovereignty," Xinhua news agency quoted Vice Foreign Minister Wang Guangya as saying.

This is "in defiance of the grave concern raised by, and repeated protests from, the Chinese government," Wang said in a meeting with a Philippine diplomat summoned to the foreign ministry, the report said.

President Gloria Arroyo signed into law the bill defining the Philippines' maritime boundaries on Wednesday.

Arroyo's chief aide, Executive Secretary Eduardo Ermita said the "baselines law" made the country's territorial claims compliant with the UN Convention on the Law of the Sea (UNCLOS) and was signed by Arroyo Tuesday.

He told reporters that the new law did not openly claim the Spratly islands and Scarborough shoal -- islets in the South China Sea that are also claimed by a number of other countries, including China.

Ermita said the Philippines had to pass the baselines law "so all our territorial claims will be based on UNCLOS," the 1982 convention which regulates international use of the world's oceans.

The Spratlys and Scarborough shoal sit astride important sea lanes and may contain significant oil and gas deposits. The islands are claimed in whole or in part by the Philippines, China, Brunei, Malaysia, Taiwan and Vietnam.