At least 20 people were killed Monday when a young female suicide bomber detonated her explosives at a bus station in Maiduguri, northeast Nigeria, in an attack likely to be blamed on Boko Haram.

The blast happened near a fish market in the Baga Road area of the city, which has been repeatedly targeted in recent weeks by shelling, bombs and suicide attacks.

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 jihadists.

The government also Wednesday announced it was banning the burqa nationwide in a security clampdown following Monday's attacks in N'Djamena that left 33 people dead and more than 100 wounded.

At least 13 people were killed and 53 others injured in northeast Nigeria when an explosive device detonated, a health official and vigilantes helping the military against Boko Haram said Wednesday.

The device was picked up by one of the vigilantes as they traveled back to the town of Monguno, in Borno state, from a military operation against the Islamists in Marte, 40 kilometers (26 miles) away.

Chad declared three days of national mourning Wednesday for the 33 people killed in twin suicide bombings blamed on Boko Haram on Monday, the first such attacks in the capital N'Djamena.

President Idriss Deby said that the "provisional" death toll had risen from 24 to 33 as he condemned the "macabre and horrible" attacks on the city's police headquarters and police academy.

Ten people were killed in twin suicide bombings in Potiskum, northeast Nigeria, a police source and a civilian vigilante assisting the military against Boko Haram told AFP on Monday.

Eight vigilantes were killed in the first blast in the Igwanda area of the city at about 12:15 pm (1115 GMT) while two died in the second outside a tavern and brothel in the Dorawa area.

Twenty-three people were killed on Monday in suicide bombings targeting police in the Chadian capital that the government said was the work of Boko Haram militants.

They were the first such attacks in the capital of the central African nation, which has been on the frontline of the regional fight against the Nigerian Islamist group.

Nigeria's President Muhammadu Buhari is planning to visit Cameroon to cement a regional fighting force against Boko Haram, he told AFP on Monday.

Buhari met his counterparts from Niger, Chad and Benin at a summit in Abuja last week but Cameroon's leader Paul Biya was noticeably absent and represented by his defense minister.

Boko Haram gunmen killed at least 43 people and burned down three villages in northeast Nigeria, residents told AFP Thursday, the latest in an upsurge of attacks by the Islamist militants.

Dozens of rebels on motorcycles stormed Matangale, Buraltima and Dirmanti in restive Borno state on Tuesday, opening fire on villagers before looting and burning homes, fleeing residents said.

Nigeria on Thursday called for one of its commanders to be put in charge of a new regional fighting force until Boko Haram was crushed, as coalition partners met to discuss military strategy.

Heads of state and government from Nigeria, Niger, Chad, Cameroon and Benin jetted in to Abuja, after two days of preparatory talks involving military top brass and defense ministers.

Three female suicide bombers died in the flashpoint Nigerian state of Borno when the explosives strapped to their bodies detonated, police said Wednesday, adding no one else was killed.

State Police Commissioner Aderemi Opadokun said the bombers died on Tuesday on their way to the state capital Maiduguri, which has been hit multiple times by Boko Haram suicide attacks.