Bogota, Colombia ? Suspected rebels ambushed an army patrol, exploded a car bomb in the capital and another bomb in Colombia’s southwest Monday, killing at least 18 people in a wave of attacks a week before the presidential inauguration.

In one of the bloodiest attacks in recent years, leftist rebels ambushed and nearly wiped out an army patrol in the province of Norte de Santander, close to the border with Venezuela.

The patrol was on its way to investigate reports of an illegal highway checkpoint when the guerrillas struck, killing 15 of the 18 soldiers in the unit, said Gen. Carlos Ospina.

The ambush coincided with a car bombing in the capital, Bogota. The bomb exploded as two trucks with 50 soldiers passed by, killing one civilian and wounding 10 soldiers. In the third attack, a bomb blast killed two soldiers and wounded six others in the southwestern province of Narino.

The deaths mark one of the deadliest days for the military since President Alvaro Uribe was first elected in 2002 on a pledge to bring peace to this country after more than 40 years on civil conflict. His second inauguration is set for Aug. 7.