JAKARTA, Indonesia (AP) _ A private transport plane crashed into a mountain in eastern Indonesia in bad weather Saturday, killing all 12 people aboard, a company spokesman said.

Benny Achmad, spokesman of the Merpati Nusantara Airline which operated the plane, said the Dutch-built Fokker F-27 slammed into the 5,455-foot Mount Kalora near Palu. The city is 970 miles northeast of Jakarta.

Rescuers using helicopters found the 12 bodies at the site in rough terrain and were struggling to evacuate them in thick fog and heavy rain, Achmad said.

He said the pilot made his last contact with the tower at 12:12 p.m. Saturday, four minutes before the plane's scheduled landing time.

The plane was flying from Balikpapan on Borneo island to Palu, the capital of Central Sulawesi.

The aircraft carried seven passengers and a crew of five, Achmad said. Its ''black box'' flight recorder hasn't been found, he said.