SANTIAGO, Chile (AP) - Police detectives arrested five people accused of firing automatic rifles in the Sept. 7 ambush of President Augusto Pinochet's motorcade, the military government announced Thursday night.

The men are being held for trial by a military court, the statement said. No formal charges were announced.

The five young men were the first of 50 suspects named by an army prosecutor to be arrested in the failed assassination attempt, in which five presidential bodyguards died and 11 were wounded. Pinochet suffered only a cut on his hand.

Francisco Cuadra, secretary general of the government, handed reporters a brief statement about the arrests. It said one suspect had received military training in Cuba and another is the son of a Communist Party official who disappeared after being arrested in 1976.

All five suspects were said to be members of the Manuel Rodríguez Patriotic Front, a rebel group that claimed responsibility for the ambush. The front is named for a Chilean independence hero and is tied to the Communist Party.

They were identified as Juan Moreno Avila, 26; Víctor Leodoro Díaz Caro, 28; Arnaldo Hernán Arenas Bejas 32; Renin Fidel Peralta Véliz 23, and Jorge Mario Angulo González, 27.

The statement said the men fired M-16 rifles at Pinochet's five-car motorcade as it headed toward the capital from his weekend home in the Andean foothills southeast of Santiago. Rockets and grenades also struck the motorcade but failed to penetrate the 70-year-old president's armor-plated Mercedes Benz.

Arenas was identified as the driver of the car that pulled a camping trailer into the motorcade's path to set up the ambush, and Díaz as the driver of one of the three other getaway vehicles.

Díaz is listed as the son of Víctor Manuel Díaz López, who was the second-ranking Communist Party official in Chile when he disappeared in 1976 three years after Pinochet seized power in a military coup. The younger Díaz went into Swedish exile after his father's arrest, the statement said.

Moreno spent 11 months in two Cuban military camps in 1984 and 1985, according to the announcement.

The government declared a 90-day state of siege the night of the ambush to combat what it called a Soviet- and Cuban-backed insurgency.