At least 23 people have died following two simultaneous suicide bombings in the capital of Chad.
Information minister Hassan Sylla Bakari said four attackers also died in the morning assaults on two police buildings in N’Djamena.
More than 100 other people were wounded, he added.
The attack as the first of its kind on the Chadian capital and came following threats from a Nigeria-based jihadist group.
Boko Haram had vowed to retaliate against Chad for aiding the Nigerian military in its fight against the militants.
There was no immediate claim of responsibility, but coordinated suicide bombings by motorcyclists are a trademark of Boko Haram.
Boko Haram had been blamed for a series of attacks on villages along the lake that divides Nigeria and Chad.