Chad said Thursday its warplanes bombed Boko Haram positions in neighboring Nigeria to avenge twin suicide bombings in the capital this week blamed on the terrorists.

Chad said Thursday its warplanes bombed Boko Haram positions in neighboring Nigeria to avenge twin suicide bombings in the capital this week blamed on the terrorists.

Chad's military vowed it would continue its "merciless" pursuit of the terrorists "so that no drop of spilt Chadian blood goes unpunished".

"In response to the cowardly and barbaric acts perpetrated by Boko Haram terrorists... the armed forces carried out reprisal air strikes on the terrorists' positions in Nigerian territory on Wednesday," the military said in a statement.

Six Boko Haram bases were destroyed in the air raids, which caused "considerable human and material losses", it said, without giving further details.

Monday's attacks on the police headquarters and a police academy in N'Djamena were the first in the capital of the central African country, which has taken a lead role in a regional offensive against the Nigeria-based Boko Haram.

No group has claimed responsibility but Chad and its allies immediately blamed the terrorists, who have carried out a series of bloody attacks in border areas of countries that share a frontier with northeastern Nigeria.

On the other hand, a large sack of home-made bombs discovered at an abandoned Boko Haram camp exploded, killing 63 people, witnesses said Wednesday of a toll many times higher than in any recent attack in northeast Nigeria.