SANTIAGO - Chilean investigators Friday began excavating an unmarked grave believed to contain remains of at least five people killed during the 17-year dictatorship of Augusto Pinochet, AFP reported.

The burial site at Cuesta Barriga, some 40 kilometers (24 miles) west of Santiago, is believed to contain the remains of five or six leftist opponents of Pinochet.

Excavation of the site is the first step in an investigation ordered by Chile's Supreme Court into new information on the fate of some 180 political prisoners who died at the hands of Chile's military.

The investigation under the supervision of Judge Hector Carreno aims to recover as many of the bodies of those victims as possible.

The bodies of more than 150 of those killed were thrown into the Pacific Ocean or in lakes or rivers, according to the information made public Sunday by President Ricardo Lagos.