Nigerian police and witnesses have linked two explosions late Friday outside the capital, Abuja, to a male and a female suicide bomber. The blasts in the towns of Nyanya and Kuje killed at least 18 people and wounded about 40 others.
Nigeria's Vanguard newspaper, quoting witnesses, said the violence began when a teenage female approached a police station in Kuje after arriving on a motorcycle taxi. That bomber was killed when her explosives detonated prematurely.
The report said a second bomber, a male, arrived a short while later at the nearby Zamfara Market, carrying a bag that exploded after he deposited it near a vendor. A witness was quoted as saying a pregnant woman and a child were among the fatalities.
No group has claimed responsibility, but authorities immediately linked the attacks to the homegrown extremist organization Boko Haram.
The latest attacks came a day after four suicide bombers blew themselves up in the city of Maiduguri, killing at least 14 people and wounding about 40 others.
A military spokesman said those attacks took place near the Ajilari railway crossing in Maiduguri, capital of Borno state. He blamed the attacks on Boko Haram, though no one had claimed responsibility by late Saturday.
Maiduguri has often been a target of Boko Haram attacks. On September 20, as many as 100 people were killed in a series of coordinated explosions suspected to be the work of the Islamist extremist group.
The attacks have continued despite promises by President Muhammadu Buhari to crush the group.
The militant group has killed more than 10,000 Nigerians since 2009 as part of a campaign to impose Islamic rule on northern Nigeria.