People clear up at the site of a bomb explosion, in Maiduguri, Nigeria, Friday, July 31, 2015.

Three bomb blasts on Sunday rocked the northeastern Nigerian city of Maiduguri, the stronghold of Boko Haram, the army said, but there were no immediate reports of casualties.

“There were three improvised explosive devices explosions at Gomari and Ajilari general area in Maiduguri at about 7:21 pm (1821 GMT),” military spokesman Sani Usman said in a statement.

“Although details are not clear, it is important to note the attacks signify high level of desperation on the part of the Boko Haram terrorists,” he said.

Local residents spoke of hearing at least two explosions within a few minutes of each other in the restive city’s densely-populated Binta Sugar area.

“We heard the first sound around 7:40 pm (1840 GMT) shortly before we entered the mosque for the last prayers of the day,” said Musa, who lives in the nearby Bulunkutu neighborhood.

“I later gathered the bomb blast occurred at Binta Sugar,” he said. A few minutes later, another bomb went off in the same area.

“There was serious fireball after the second explosion,” added another local resident, Ndahi Mache.

It was not clear if there were any casualties but police, soldiers and civilian vigilantes have cordoned off the area, witnesses said.

Usman confirmed that members of the security forces had been deployed to the area and said the army was determined to defeat “Boko Haram terrorists in the shortest possible time.”

The military has made a series of gains against Boko Haram after President Muhammadu Buhari recently set a three-month deadline to wipe out the extremists.