MANILA - PXP Energy has sent "feelers" to China National Offshore Oil Corp to resume negotiations on possible joint exploration in the disputed South China Sea, its chairman said Wednesday.

PXP Energy Chairman Manuel Pangilinan refused to elaborate. Asked if CNOOC replied, he told reporters: "I can't say."

PXP Energy sought to reopen communication lines with the Chinese company as tensions between the Philippines and China eased under President Rodrigo Duterte, who has sought to boost economic ties with Beijing while distancing Manila from Washington, its traditional ally.

The company, formerly known Philex Petroleum, controls Forum Energy, which in turn has a 70-percent stake in Service Contract 72, off western Palawan.

Talks between Philex Petroleum and CNOOC stalled under President Benigno Aquino, after the Philippines protested China's moves in the disputed waterway, which is believed to hold vast oil and gas reserves. -- Report from Michelle Ong, ABS-CBN News