BANGKOK  — A Lao air force plane carrying senior government officials crashed Saturday, killing at least five people on board, including the country's defense minister, Thai officials said.

The Russian-made plane, believed to have had about 20 people on board, left from the capital, Vientiane, early Saturday morning headed for an official ceremony in the northeastern province of Xiangkhoung, about 290 miles away, said Thai Foreign Ministry spokesman Sek Wannamethee.

It crashed in a forested area of Xiangkhoung province, near one of Laos' major archaeological sites, the Plain of Jars.

Among those confirmed killed in the crash were Defense Minister Douangchay Phichit and his wife, said Nipat Thonglek, the Thai defense ministry's permanent secretary.

Douangchay was also one of the country's deputy prime ministers and a high-ranking member of Laos' Politburo, the main decision-making body for the nation's ruling Communist Party.

Also killed were the governor of the capital of Vientiane, Sukhan Mahalad, and two other senior officials, Nipat said. He said he was given the information by authorities in neighboring Laos who did not immediately release details of the other passengers.

The cause of the crash was not immediately known.

Lao National Television showed images of the aircraft in a wooded area with smoke rising from its badly charred remains.

Thailand's Thai Rath newspaper identified the plane as a Russian-made Antonov AN-74.

In October, a Lao Airlines ATR-72 turboprop crashed during a heavy storm as it approached Pakse Airport in southern Laos, killing all 49 people on board.