At least 21 people were killed in a blast in the Mardan district in Pakistan's Khyber Pakhtunkhwa Province on Tuesday. The explosion took place near the office of the National Database and Registration Authority (Nadra). 

A suicide bomber on a motorbike reportedly detonated his vest when he was stopped from entering the office gates. Jamaatul Ahrar, splinter group of the Pakistan Taliban wing, Tehreek-eTaliban, claimed the attack, Dawn reported.

"This office was attacked because it is an important institution of the infidel state of Pakistan," Ehsanullah Ehsan, spokesperson of the Taliban faction, told AFP. 

At least 45 people were injured. The building that houses the Nadra office was also damaged,  as per reports. The Nadra issues ID cards and offers e-governance services in the country. 

Pakistani media cited officials saying that the death toll is likely to rise. 

The suicide bomber was carrying about 8 kilogrammes of explosives, according to The Express Tribune.