A suicide bomber blew himself up outside a government office in a northwestern Pakistani city on Tuesday, December 29, killing at least 22 people and wounding 45. A breakaway Taliban group quickly claimed responsibility for the attack, the Associated Press reports.

The bombing took place in the city of Mardan, outside the regional office of the National Database and Registration Authority, or NADRA, which issues identity cards to Pakistanis, according to senior police officer Saeed Khan Wazir.

Wazir told the Associated Press that some of the wounded were in a critical condition.

Shortly after the attack, a spokesman for the militant Jamaat-ul-Ahrar group, Ahsanullah Ahsan, claimed responsibility for the bombing, calling it a "noble act to punish NADRA because it extends support to security forces." Ahsan spoke to the AP by phone from an undisclosed location.

Jamaat-ul-Ahrar split from the main Pakistani Taliban group — the Tehrik-e-Taliban Pakistan or TTP — two years ago following differences between the militant leadership.

Prime Minister Nawaz Sharif condemned the bombing and instructed authorities to provide the best possible treatment for the wounded.