By Garba Muhammed
KADUNA, Nigeria (Reuters) - Suicide bombers killed around 30 people in two blasts in northern Nigeria on Tuesday, witnesses and a state governor said, the latest attacks in a renewed offensive by suspected Boko Haram insurgents.
There were no immediate claims of responsibility for the attacks but they bore hallmarks of the Islamist militant group, which has bombed several towns and cities in northern Nigeria in the last 10 days after months when they were thought to be hiding out in the Sambisa forest.
Last week, more than 200 people died in a string of attacks in Africa's top oil producer, piling pressure on new President Muhammadu Buhari who is trying to work with neighboring states to quell the insurgency.
An attacker detonated a device on Tuesday at a local government building on the outskirts of the city of Zaria, killing 25 people and wounding 32 others, Nasir el-Rufai, governor of Kaduna state, said on Twitter.
Zinari Shehu, a local radio journalist, said the bomb went off in a suburb where people had gathered to greet a newly-appointed head administrator. There were conflicting reports as to whether the bomber was male or female.
Witnesses and a military source said a female suicide bomber killed four people around the same time at a military checkpoint in Sabon-Gari town in the northeastern state of Borno, which has been hit hardest by the insurgency.
"A young lady wearing a veil with explosive devices strapped at her body detonated an IED at a checkpoint ... before she was checked," the military source said.
Boko Haram has been trying to establish a state adhering to strict sharia law through an insurgency that began in 2009. It controlled an area larger than Belgium at the end of 2014.
Nigerian and regional forces have joined together to push the jihadists out of most of that territory but the militants have a last stronghold in the Sambisa forest reserve and many have dispersed throughout the country.
(Additional reporting by Isaac Abrak in Abuja; Writing by Alexis Akwagyiram; Editing by Ruth Pitchford)