BOGOTA, Colombia (AP) Rebels firing homemade rockets attacked a military post in southwestern Colombia on Tuesday, killing at least 14 soldiers and wounding about 25, the navy said, describing the bloodiest rebel attack in two years.

Government forces in river gunboats, a ``Phantom'' fixed-wing gunship and helicopters were pursuing the rebels of the leftist Revolutionary Armed Forces of Colombia, or FARC, who attacked the post in Iscuande county, the navy said in a statement.

The attack came amid a government offensive, called Plan Patriot, deep into the rebel's jungle hideouts in southern Colombia, more than 150 miles from the site of Tuesday's attack. Despite blows suffered by the rebels in the campaign, the attack suggested they retain the capability of striking in diverse points of this Andean nation.

FARC rebels used large gas cylinders converted into rockets in the predawn attack on the outpost, located near where the Iscuande River empties into the Pacific Ocean, the navy said.

A lieutenant who commanded the outpost and 13 other marines were killed in the pre-dawn attack, Adm. Mauricio Soto, the commander of the Colombian navy, told a news conference in the capital, Bogota.

Some of the troops at the base were so-called campesino marines, or peasant marines, who are natives of the area where they are stationed and who receive three months of military training.

The deployment of thousands of campesino troops in Colombia to protect their own villages and farms from the rebels is a major component of hardline President Alvaro Uribe's strategy to bring Colombia's 40-year-old insurgency to its knees.

The attack occurred in Narino state, which hugs the Pacific Ocean and the Ecuadorean border and is a major cocaine-producing center. Colombian counternarcotics troops were assisting in the pursuit of the rebels, the navy said.

The United States has given Colombia about $3 billion in mostly military aid since 2000 to combat the rebels and to curb cocaine and heroin production, which help fund the war. U.S. Special Forces have trained Colombian counternarcotics troops.

Tuesday's attack by the FARC was the bloodiest since Feb. 14, 2003, when rebels wired a house in the southern city of Neiva with explosives and detonated it as police entered, killing 17 people, including nine police officers.