BOKO HARAM was accused of an “appalling and barbaric attack” yesterday when suicide bombers struck Chad’s capital for the first time, killing at least 23 people.

Two bombers riding motorcycles blew themselves up outside the national police academy in N’Djamena; another two attacked the office of the police chief. The explosions killed passers-by as well as people inside the targeted buildings.

The government issued a statement blaming Boko Haram, the Nigerian Islamist movement, adding: “These lawless and faithless terrorists will be flushed out and neutralised wherever they are.”

If Boko Haram was responsible, these would be the first suicide bombings organised by the movement in an African capital outside Nigeria. Chad has deployed thousands of troops across the border in Nigeria to fight Boko Haram. The country’s 20,000-strong army, battlehardened by years of civil war, has been the backbone of an offensive which has successfully broken the terrorist movement’s control of thousands of square miles of north-eastern Nigeria.

But Chad’s intervention has also exposed the country to retaliation. The gunmen have already attacked villages near the border with Nigeria. The bombings in N’Djamena show that while Boko Haram might have lost territory and suffered a string of defeats, the movement remains capable of urban terrorism.

Hassan Sylla Bakari, the Chadian information minister, denounced an “appalling and barbaric attack”.

The bombings “will not diminish Chad’s determination and commitment to fighting terrorism”, he added.