BOGOTA  - Colombian troops killed 33 FARC rebels during a gun battle in the country’s Arauca province, military officials said Wednesday, calling it one of the biggest strikes in years against the leftist insurgency.

The country’s defense chief Juan Carlos Pinzon told reporters that the rout of the rebels in the joint air force and army operation overnight was “without a doubt one of the hardest strikes of the past five years” against the FARC.

The operation was carried out in eastern Colombia, in the region bordering Venezuela, and occurred in the same area where over the weekend rebels with the FARC (the Revolutionary Armed Forces of Colombia) ambushed an army unit, killing 11 soldiers.

In a Twitter message earlier Wednesday, President Juan Manuel Santos hailed what he called “a huge blow against the FARC in Arauca where they killed our soldiers,” and gave a preliminary estimate of 24 rebels killed.

The violence follows FARC overtures — thus far deemed insufficient by the government — to make peace with Bogota.

The FARC, Latin America’s last major insurgency, said through a mediator Wednesday it plans to release 10 military hostages, under a pledge announced last month.

The rebel group announced last month it would free the 10 members of the military and police forces that it still holds and would and end the practice of kidnapping for ransom. The group said Wednesday those releases would begin on March 26.

The FARC has continued however to be active in clashes with army forces.

Santos has said he would open a direct dialogue with the leftist rebels only when all hostages are released and the group vows to cease “terrorist” actions. He also wants the FARC to stop recruiting children.

The FARC, believed to have 8,000 members, has been at war with the government since 1964. It began a campaign of kidnappings in the mid-1980s, seizing army hostages to serve as bargaining chips for FARC prisoners.