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 extremist group.
“Boko Haram chose the wrong target. These lawless and faithless terrorists will be flushed out and neutralised wherever they are,” the government said in a statement.
It said 23 people were killed and another 101 wounded in the simultaneous bombings outside the police headquarters and police academy in N’Djamena.
It said four “terrorists” were also killed, but did not give details. Earlier, a police official had told AFP that two suicide bombers carried out the attacks, which came as police cadets were attending a training course at the academy.
There was no immediate claim of responsibility.
The government said the situation was quickly brought under control, but the unprecedented assault on the capital prompted the creation of a “crisis cell” and vehicles with darkened windows were banned from N’Djamena.
Large numbers of members of Chad’s security forces were also seen taking up positions on the streets.
President Idriss Deby was expected to return home during the day from an African Union summit in Johannesburg, an official said.
In his absence, government ministers held a crisis meeting to discuss the bombings.
The former French colony is part of a four-nation coalition also including Nigeria, Cameroon and Niger that was created to tackle the Boko Haram insurgency after the group stepped up cross-border attacks.
Boko Haram leader Abubakar Shekau has on several occasions threatened to attack Chad and other countries in the coalition.
Paris condemned Monday’s blasts, with a foreign ministry spokesman saying France “stands alongside Chad and its partners in the fight against terrorism”.
Chad is a close ally of France in its counter-terrorism Operation Barkhane in five countries in the Sahel region and the French army has set up its headquarters for the campaign in N’Djamena.
Last week, Abuja hosted a summit where Nigeria and fellow coalition members plus Benin rubber-stamped an 8,700-strong regional force to replace the current four-nation grouping.
The long-awaited Multi-National Joint Task Force, which had originally been due to become operational in November, has its headquarters in N’Djamena, under a senior Nigerian officer.
Boko Haram has been waging a six-year campaign of violence in northeastern Nigeria that has left at least 15,000 people dead and increasingly spilled across borders.
Chad’s involvement in the fight against Boko Haram began in January when Deby sent troops to assist neighbouring Cameroon, whose far northern region was coming under attack from the rebels.
More than 70 Chadian soldiers have died in operations against the extremists, including attacks around Lake Chad where the borders of Nigeria, Chad, Cameroon and Niger meet.
Nigeria’s new President Muhammadu Buhari, who has vowed to make crushing Boko Haram the priority of his rule, visited Chad as well as Niger earlier this month to build up the regional coalition against the extremists.
“Boko Haram declared that they are in alliance with IS, so terrorism has gone international. They are in Mali, they are in Nigeria, they are in Syria, they are in Iraq, they are in Yemen,” he told AFP at the summit in South Africa on Monday.
“It’s an international problem now,” he said.
Boko Haram, whose name roughly translates as “Western education is forbidden”, aims to create an obscurantist state in the territories it controls and earlier this month declared allegiance to the IS.
Some of the 1.5 million people made homeless by the violence have fled to Chad, a poor, largely desert landlocked country.
Meanwhile, in Nigeria two bomb attacks in the northeastern city of Potiskum killed 10 people on Monday, eyewitnesses and a hospital source said.
The first bomb exploded at around 1 pm (1200 GMT) in the office of a group set up to defend local people against such attacks, eyewitnesses said. A suicide bomber detonated a device at an outdoor tea drinking area a few minutes later.
“I heard a loud sound… It shook the whole of the area,” said Babagana Aminu, a shopkeeper based near the first bomb site, told Reuters by telephone.
There was no immediate claim of responsibility but the bombings bear the hallmarks of attacks by Boko Haram.
A source in Potiskum hospital said a total of 10 people – eight males and two females – were killed in the attack in the explosions in northern Nigeria.
Last week new President Muhammadu Buhari convened a summit in Abuja with counterparts from Chad, Niger, Benin and Cameroon to set up a regional task force to fight Boko Haram.
At the start of this year the militants controlled an area of northeast Nigeria around the size of Belgium but the military said it had pushed them out of most of those areas, at times with the help of troops from neighbouring countries.
A spate of bombings in the northeast has marked an apparent resurgence of Boko Haram that has seen around 100 deaths in the last few weeks.