The Colombian army killed 18 guerrillas from the Revolutionary Armed Forces of Colombia (FARC) on Thursday in bombing raids, followed by ground attacks. The latest attack against the rebels was one of the deadliest since President Juan Manuel Santos restarted suspended airstrikes last month.

The bombing took place in the Cauca department on the Pacific coast, an important location for drug traffickers, where FARC rebels have a large presence, Reuters reported. The five-decade long conflict between the government forces and the FARC guerrillas has killed over 220,000 people and displaced over 5 million.

"It is the first major blow against FARC since President Santos ordered the resumption of air strikes against the guerrillas on April 15," an official from the country’s defense ministry said, according to Agence France-Presse.

The suspension of airstrikes was lifted after FARC rebels broke a unilateral ceasefire in April and attacked a mountainous area in the Cauca department in southwestern Colombia. At least 10 soldiers were killed in the assault and 20 others were injured, jeopardizing the peace talks between the warring sides that began over two years back.

"I have ordered the armed forces to ignore the order suspending bombings of FARC camps until further notice," Santos had said last month, according to the Telegraph, adding: "Let this be clear to the FARC: I'm not going to be pressured ... by vile acts like this to make a decision on a bilateral ceasefire."

FARC, which was formed in 1964, has deployed about 8,000 fighters in the rural parts of the country, the Telegraph reported.