The former deputy head of military intelligence in Guinea Bissau, colonel Samba Diallo, was killed on a street in the capital Bissau by men wearing military uniforms, military and security sources told AFP Monday.

The killing happened late Sunday, just hours after polls closed in the first round of the presidential elections.

Diallo's attackers, whose identities are not yet known, shot him as he was seated at the terrace of a restaurant across from his home in a neighbourhood near the center of the city, a soldier, a witness to the attack and a representative of an NGO, all of whom requested anonymity, told AFP.

"They shot at him over five times," a police source said, adding that his body was taken to his home.

A security official who went to Diallo's home overnight confirmed his death.

Diallo, until April 2010, was deputy director of military intelligence. He was arrested along with other top officers on suspicion of involvement in the 2009 deadly bombing that killed the country's army chief.

Diallo was released after eight months and since then has had no official responsibilities in the army.