Female suicide bombers are suspected to be behind the twin explosions that rattled the northeastern Nigerian city of Maiduguri on Saturday near a refugee camp and a fuel depot, officials said.

The attacks targeted the city’s Bakassi Internally Displaced Persons camp and the Nigerian National Petroleum Corp.’s Mega Filling Station, the Nigerian army said in a statement.

At least nine people were killed and 24 injured in the two explosions, according to the country's National Emergency Agency (NEMA).

In the first attack the suspected bomber ran into a crowd at the entrance of the Bakassi IDP camp, killing five people, the army said.

Ten minutes later and a mile away, a second blast killed three occupants on a motorized rickshaw at the entrance of a fuel depot owned by the National Oil Company. The army puts the total number of dead at 8.

“While we commiserate with the families of the late victims of this cruel act and wish those injured speedy recovery, we would like to assure the public that efforts are ongoing to track those behind the dastardly acts,” an army spokesman said.

“However, it is equally important to reiterate the need for more vigilance and security consciousness among all.”

Terror group Boko Haram is suspected to be behind the blasts, said Maiduguri military chief Brig. Gen. Victor Ezugwu and NEMA's northeast region head Mohammed Kanar.

Militants from the Islamic extremist group are firmly entrenched in Nigeria's northern states. In their seven-year insurgency against the

Nigerian government Boko Haram has killed thousands, kidnapped hundreds of schoolgirls and sought to establish a puritanical Islamic state in the country.

The most recent Global Terrorism Index cited Boko Haram as the world’s deadliest terrorist group in 2014 for its killings in Nigeria, Chad and Cameroon. In March 2015, Boko Haram pledged allegiance to ISIS, the extremist terror group that has launched attacks across the globe. (CNN)

•Photo shows scene of the blasts.