Philippine President Benigno Aquino says the country's newest warship will be deployed to protect the nation in areas where oil exploration vessels have reported run-ins with China.

Mr. Aquino spoke Tuesday as he and other top officials inspected the BRP Gregorio del Pilar, a decommissioned U.S. Coast Guard cutter acquired by the Philippines navy in May. The 46-year-old ship will be the most capable vessel in a fleet made up of mostly World War II-era ships.

Mr. Aquino said the ship will be used, among other purposes, to guard exploration efforts in the Philippines' exclusive economic zone in the South China Sea. He said the ship represents the nation's readiness to defend its interests, and that his government's defense build-up will continue.

Other countries with competing claims in the South China Sea are also strengthening their navies. China this month conducted sea trials of a refitted aircraft carrier, while Vietnam this week took ownership of a Russian-made guided missile warship. Vietnam acquired a similar Russian-made ship in March.

The Gregorio del Pilar entered the Philippines last week after a month-long voyage from the U.S., and has been undergoing customs, immigration and quarantine inspections in Manila Bay.

The refurbished ship is manned by 95 officers and enlisted personnel. It will perform such missions as drug interdiction, law enforcement, and search and rescue operations as well as protecting oil and gas exploration projects.