The Philippine navy has removed foreign marker posts installed on three reefs and banks in the disputed waters of the South China Sea, which Manila now calls the West Philippine Sea.

Officials said Wednesday the unidentified posts were removed in May from Reed bank, Boxall Reef and Amy Douglas Bank, shortly before the government protested China's alleged incursions in Philippine territorial waters.

Chinese Foreign Ministry spokesman Yang Yi reiterated Beijing's position Wednesday, saying that China has indisputable sovereignty in the area. The disputed region comprises the uninhabited Spratly and Paracel islands and their surrounding waters in the South China Sea.

Beijing has also been involved in a maritime dispute with Vietnam after Chinese vessels twice interfered with oil survey ships operating off Vietnam's coast.

Vietnam and the Philippines have both sought U.S. backing in the disputes, drawing a sharp rebuke from the Chinese government.

The United States has expressed support for a peaceful resolution of the conflict and for freedom of movement in the disputed waterway.

Brunei, Malaysia and Taiwan also have overlapping territorial claims in the region, which is believed to contain vast oil and gas reserves.

China, Vietnam, the Philippines, Taiwan, Brunei and Malaysia claim all or part of the Spratly Islands. China, Vietnam and Taiwan also claim the Paracel.

Philippine presidential spokesman Edwin Lacierda Wednesday welcomed assurances by China's Foreign Ministry that China will not resort to the use of force. He said Manila has always maintained that there should be a peaceful resolution to the maritime dispute.

U.S. Senator Jim Webb, , Monday urged Congress to condemn China's actions in the disputed waters.

China has said it is “firmly opposed” to foreign involvement in the regional disputes, but said it wants to resolve the conflict peacefully.