Security officers stand at the site of a suicide bombing in Ndjamena, Chad, June 15, 2015. At least 27 people, including four suspected Boko Haram Islamist fighters, were killed and 100 others were injured on Monday in two attacks in Chad's capital, N'Djamena, which the government blamed on the Nigerian militant group. REUTERS/Moumine Ngarmbassa (Stringer/Reuters)

Suicide bombers in Chad’s capital attacked security hubs Monday, killing at least 23 people in strikes that raised fears of a widening reach by the Islamist faction Boko Haram, reports said.

There was no immediate claim of responsibility for the series of blasts in the Chadian capital, N’Djamena.

But suspicion immediately fell on Boko Haram militants, whose strongholds in nearby Nigeria have come under increasing pressure from a five-nation African military coalition that includes Chad.

The Associated Press, citing Chad’s information minister, said at least 23 people were killed in back-to-back attacks at sites linked to Chad’s police, including a training academy. Chad’s government spokesman said four suspected Boko Haram militants also died in the assaults, the Reuters news agency reported.

The various reports on the death toll also noted the count was preliminary, suggesting it could rise.

“Boko Haram is making a mistake by targeting Chad,” Chad’s communications minister, Hassan Sylla Bakari, said on state television without offering specific details on why he pointed the finger at the group.

“These lawless terrorists will be chased out and neutralized wherever they are,” he added.

Chad’s capital, the headquarters for the alliance, has so far been spared major retaliatory strikes by Boko Haram. N’Djamena is also the base for a French military mission battling militants in the region.

In March, Chad hosted U.S.-led counterterrorism exercises that included 20 African nations.

Security forces in the vast country — stretching from West Africa to the Libyan border — also has battled militant groups that include a branch of al-Qeada.

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