Nigerian troops have arrested the mastermind of bombings in the central cities of Jos and Zaria this week that killed at least 69 people, the defence ministry said on Thursday.

No one has taken responsibility for the attacks but they bore the hallmarks of Islamist sect Boko Haram, which has been waging a six-year insurgency in Africa's largest oil producer.

"The highly placed terrorist was arrested with two others who were in his company. One of them was however shot while trying to escape," the defence ministry said.

The suspect was picked up at a checkpoint in the northeast city of Gombe, on the fringes of Boko Haram's northeast stronghold, it added.

The Jos blast claimed 44 lives while 25 people were confirmed dead in the Zaria attack.

Last week, more than 200 people died in a string of attacks across the nation, piling pressure on President Muhammadu Buhari who is working with neighbouring states to quell the insurgency.

A joint operation by Nigeria military and its neighbours has reduced attacks in recent months but bombings in the centre of the country suggests Boko Haram may be shifting its focus further south and west, towards the capital, Abuja.