AFP/ N'Djamena

Chad executed 10 alleged members of Nigeria-based militant group, Boko Haram, by firing squad Saturday, a day after they were found guilty of a double suicide killing that left 38 people dead in the capital N'Djamena.

"They were executed this morning on a shooting ground north of N'Djamena," a judicial source told AFP. The report was confirmed by a security source who asked not to be identified.

The 10 were condemned to death Friday in the country's first trial of presumed members of the group. The hearings opened Wednesday.

Nigeria's neighbours Chad, Cameroon and Niger have all suffered attacks by Boko Haram and earlier this year they announced a regional force to end the militants' insurgency that has claimed more than 15,000 lives since 2009. 

The defendants were accused of criminal conspiracy, killings, wilful destruction with explosives, fraud, illegal possessions of arms and ammunition, as well as using psychotropic substances.

The accused include Nigerian national Mahamat Mustapha, also known as Bana Fanaye, who according to Chadian authorities masterminded the June 15 suicide attacks that struck a school and a police building in N'Djamena, killing 38 people and injuring 101.

On July 12, a fresh attack in the Chadian capital claimed by Boko Haram left at least 15 dead and 80 hurt after an assailant dressed as a woman blew himself up in the central marketplace.

Shortly after Fanaye's arrest in late June, Chad's top prosecutor Alghassim Kassim said the suspect was the "ringleader of a network smuggling weapons and munitions between Nigeria, Cameroon and Chad".

Chad has beefed up security in response to the bloodshed.

The regional force against Boko Haram is expected to number some 8,700 troops and police, but it has yet to go into action