The Colombian army has killed at least 33 members of the country's Revolutionary Armed Forces (FARC) in the oil-rich Arauca province, the government announced Wednesday.

The army has dealt "a great blow against the FARC in Arauca, where they killed our soldiers," Colombian President Juan Manuel Santos announced via his Twitter account.

Last Saturday in Arauca, FARC rebels launched an explosive device against an army patrol team, killing 11 soldiers.

The FARC often targets oil companies in the region in eastern Colombia that borders Venezuela.

Initially, Santos said 24 rebels had been killed by the Army, but Defense Minister Juan Carlos Pinzon later told reporters at a press conference that the rebels' death toll had reached 33.

Colombian Army Commander Ernesto Maldonado described the deaths as the strongest blow against the FARC this year.

Santos ended his Twitter message with "congratulations to our forces."

Five rebels were also captured, including the "second in command of the FARC front," who goes by the alias "Misael," said Pinzon.

Pinzon said "Misael", who has an extradition order and has been a FARC member for 29 years, is responsible for "multiple crimes".

During the attack on the rebels, the army also seized a cache of weapons, including machine guns and grenade launchers.