ABUJA (Reuters) - Police said they had arrested the suspected mastermind of bombing attacks by the Islamist militant group Boko Haram that killed 15 people in the Nigerian capital Abuja in 2015.

The force named the man as Umar Abdulmalik and said he and other people they arrested had confessed to the bombings, the jailbreak of more than 100 prisoners in June, the killing of seven police officers in July and various bank robberies.

There was no comment from any lawyer representing Abdulmalik, who police said was arrested in the commercial capital Lagos on Thursday.

Police issued a photograph of Abdulmalik in handcuffs in front of a van, and another of seven other men in front of weapons, walkie-talkies, credit card point-of-sale machines and ammunition.

More than 30,000 people have been killed and millions forced to flee in Boko Haram’s decade-long campaign to carve out an Islamist state in northeast Nigeria.

A military campaign by Nigeria and its neighbors has pushed the group out most of its territory since the beginning of 2015, but fighting has rumbled on.

Over the past year, a splinter group allied with Islamic State has become the dominant branch, killing hundreds of soldiers and frequently overrunning military bases.