A judicial commission was ambushed by leftist guerrillas in eastern Colombia, and only two of its members escaped alive, the army said. Two judges were among the 13 people killed.

"It is an unprecedented attack on investigators who did not constitute an attack force," Carlos Eduardo Lozano, director of criminal judges, said of Wednesday's attack near the port city of Barrancabermeja.The commission - consisting of judges Mariela Morales, 35, and Pablo Beltran, 40; two secretaries; nine judicial police officers and two drivers - was investigating the October 1987 disappearance of 17 merchants and $235,000 in goods.

The attackers set off dynamite charges under a road as two vehicles carrying the party passed, then opened fire with automatic weapons.