MANILA, Jan. 10 -- The Supreme Court has struck down as unconstitutional an agreement signed in 2005 for mineral "pre-exploration" in the South China Sea.

In a statement on Tuesday, the SC said it voted 12-2-1 to void the Joint Marine Seismic Undertaking (JMSU) by and among China National Offshore Oil Corporation, Vietnam Oil and Gas Corporation and Philippine National Oil Company, covering 142,886 square kilometers.

The tribunal said the tripartite agreement, signed on March 14, 2005, is unconstitutional for allowing wholly-owned foreign corporations to participate in the exploration of the Philippines' natural resources without observing the safeguards provided in Section 2, Article XII of the 1987 Constitution.

All lands of the publ...