BOGOTA (Reuters) – Between 30 and 40 members of Colombia’s biggest rebel army were killed when government forces bombed their position in the mountainous central province of Tolima, a local official said yesterday.

The raid marked one of the hardest blows this year against Marxist FARC guerrillas, who have been pushed deeper into rural areas by President Alvaro Uribe’s US-backed security measures.

A local FARC leader known as Jeronimo may have been killed in Thursday’s raid, Tolima Governor Oscar Barreto told local radio.

The once 17,000-member guerrilla group has been reduced to about 9,000 fighters, according to security officials.

Uribe, popular for making the cities and highways safer and for encouraging investment in this Andean country, may stand for a third four-year term in 2010 if his supporters manage to pass a constitutional amendment allowing him to run.