The Colombian government gave no figures for military casualties resulting from Sunday's fighting [File: AFP]

The Colombian military said it has killed at least 22 anti-government fighters in an offensive involving aerial bombardment and ground troops near the border with Ecuador.

Rodrigo Rivera, the Colombian defence minister, said the government had "dealt a serious blow" to the Revolutionary Armed Forces of Colombia [Farc] rebels operating in the remote southern Putumayo province.

"Up to now 22 narcoterrorists have been killed," Rivera said in a phone call to Juan Manuel Santos, the Colombian president, on Sunday.

Rivera gave no figures for military casualties in the fighting, which erupted in an area where eight police officers were killed on September 10.

Soldiers, police and air force warplanes were involved in the operation, which was launched "entirely within Colombian territory", Rivera said.

Ties between Ecuador and Colombia remain strained since March 2008 when the Colombian military raided a Farc camp located just across the border with Ecuador.

This time, Rivera said he contacted Miguel Carvajal, the Ecuadoran security minister, to inform him of the operation and later thanked him for helping stop Farc fighters from fleeing into Ecuador.

Farc has reportedly killed more than 30 police in attacks across Colombia since Santos became president on August 7.