At least 14 people were killed and dozens wounded when two bomb blasts went off at a district court in northwestern Pakistan, officials said.

A suicide bomber threw a hand grenade at police guards before storming into the compound and blowing himself up in the court in Mardan town in Khyber-Pakhtunkhwa province.

Nasir Khan Durrani, provincial police chief, told AFP news agency that the death toll had reached 14, with at least 58 people wounded, three of whom were critical.

Officials said the bomber had up to eight kilogrammes of explosives packed into his vest, while the dead included lawyers and police.

Amir Hussain, president of the Mardan Bar Association, said lawyers were being targeted because they are "an important part of democracy, and these terrorists are opposed to democracy".

"Our morale is not dented. It is still high," he told AFP.

Earlier, four suicide bombers who were trying to attack a Christian colony were killed during a gunfight with security forces outside the northwestern city of Peshawar, the army said.

Soldiers backed by army helicopters fought back the fighters who had tried to attack the colony near Warsak Dam, just north of Peshawar.

Asim Bajwa, an army spokesman, said "all four suicide bombers were killed" in the operation carried out against the fighters on Friday and that a clearance operation was under way.

Local sources, though, told Al Jazeera that at least one civilian was killed and several wounded in the attack.

Two of the four suicide bombers detonated their vests and the other two were shot dead, the sources said.

Pakistani Taliban faction Jamaat-ur-Ahrar claimed responsibility for the attacks.

The group's spokesman, Ehsanullah Ehsan, promised more attacks in a statement released to media.

"We appeal to civilians to remain away from law enforcement installations and these un-Islamic courts. We will target them more," he said.

Al Jazeera's Kamal Hyder, reporting from Islamabad, said despite army claims to have limited the number of attacks, armed groups still managed to operate across the country.

"Just yesterday the Pakistan military gave a press conference in which they said they had been able to control the number of attacks in the country," he said.

"But it appears that the Tehreek-e-Taliban and their factions are still able to operate within Pakistan and carry out these attacks."

Last month, the Pakistan Taliban faction and the Islamic State of Iraq and the Levant (ISIL,also known as ISIS) both claimed responsibility for a suicide attack at a hospital in Pakistan's Quetta that killed at least 70 people.

The attack targeted a group of mourning lawyers, who had gathered at the emergency department of the hospital to accompany the body of a murdered colleague.

The Pakistan army launched Operation Zarb-e-Azb under US pressure in 2014 in an effort to wipe out fighters and their bases in the North Waziristan tribal area.