Human Rights activists in Guatemala said Friday that a joint anti-drug operation between U.S. Marines and the nation's army threatens to revive memories of rights abuses during Guatemala's 1960-1996 civil war.

A team of 200 U.S. Marines began patrolling Guatemala's western coast this week as part of a joint agreement to catch drug shipments.

"Rural communities in Guatemala are fearful of the military being used to combat drug traffickers because the same techniques are applied that were used in contra (counterinsurgency) warfare," said rights advocate Helen Mack, executive director of the Myrna Mack Foundation. "The historical memory is there and Guatemalans are fearful of that."

Kelsey Alford-Jones of the Guatemala Human Rights Commission/USA noted that Guatemalan armed forces, which were backed by the U.S. during the civil war, committed more than 93 percent of the acts of violence.

It was 50 years ago when the U.S. military last sent any significant aid and equipment into Guatemala, establishing a base to support counter-insurgency efforts during a guerrilla uprising after a CIA-backed coup overthrew democratically elected president Jacobo Arbenz in 1954. The movement led to 36 years of civil war that ended in 1996 with the signing of a peace accords between the government and leftist guerrillas.

The conflict left more than 200,000 dead and missing, 93 percent of them as a result of the activities of state forces and paramilitary groups, a U.N. report said. The U.S. pulled out in 1978.

Guatemalan authorities say they signed a treaty allowing the U.S. military to conduct the anti-drug operations on July 16. Less than a month later an Air Force C-5 transport plane flew into Guatemala City from North Carolina loaded with the Marines and four UH-1 "Huey" helicopters.

If the Marines find suspected boats, they will contact their Guatemalan counterparts in a special operations unit from the Guatemalan navy that will move in for the bust. The Marines will not go along on arrest missions, but they do have the right to defend themselves if fired on, U.S. officials said.

"Marines in Guatemala are in a supporting role and we are providing aerial, communications and logistical support to a regional partner who is currently facing strong challenges with illicit trafficking along its coasts. This is not a new role nor the first time the U.S. military supports a partner in this capacity," said Army Lt. Col. Todd Breasseale, a spokesman for the U.S. Defense Department in an email response to an AP query.