A suicide bomber killed at least 12 people and injured dozens more in Pakistan's capital Islamabad on Tuesday.

The blast occurred outside the district court complex in Islamabad around 12:30 p.m., an area usually crowded with lawyers, judges and litigants attending daily hearings. Local media footage showed bloodstained victims lying beside a burning police van, as emergency workers rushed to the scene.

The Pakistani Taliban, known as Tehreek-e-Taliban Pakistan (TTP), claimed responsibility for the attack. It said in a statement that "judges, lawyers and officials who carried out rulings under Pakistan's un-Islamic laws were targeted," threatening more assaults until the Islamic law was implemented in the country.

Pakistani ministers accused neighboring Afghanistan of complicity in the bloodshed – an accusation Kabul denied – and vowed retaliation if Afghan authorities failed to rein in the militants.

"We are in a state of war," said Defence Minister Khawaja Muhammad Asif after the attack, the first strike on civilians in Islamabad in a decade. "Bringing this war to Islamabad is a message from Kabul, to which Pakistan has the full power to respond."

Tensions with Afghanistan rise

Relations between Islamabad and Kabul have deteriorated sharply in recent months. Deadly clashes erupted along their shared border last month, leaving dozens dead, as both sides traded accusations over cross-border attacks. Talks aimed at maintaining a fragile ceasefire have yet to yield results.

Pakistan insists that TTP and other militant groups operate from sanctuaries inside Afghanistan, allegedly with India's backing – a claim both Kabul and New Delhi have denied.

"We are totally clear that Afghanistan has to stop them. In case of a failure, we have no option but to take care of those terrorists who are attacking our country," Interior Minister Mohsin Naqvi said, speaking at the scene of the court bombing.

India's foreign ministry dismissed Pakistan's claims, saying New Delhi "unequivocally rejects the baseless and unfounded allegations being made by an obviously delirious Pakistani leadership."

The Taliban administration in Kabul expressed "deep sorrow and condemnation" over the bombing but did not respond to questions about Pakistan's accusations. Kabul maintains that its territory is not used to launch attacks on other countries.

The attack

Authorities said the bomber blew himself up near a court entrance at around lunchtime.

Naqvi said the bomber had tried to enter the court building on foot but, unable to find a way in, detonated the device outside, close to a police vehicle. Several of the wounded were in critical condition, a hospital source said.

Videos of the incident on Tuesday showed a blackened car that had been targeted by the bomber. Witnesses described hearing a loud bang and seeing bodies lying on the floor near the court complex.

"It was complete chaos. Lawyers and people were running inside the complex. I saw two dead bodies lying on the gate and several cars were on fire," Rustam Malik, a lawyer, told AFP.

(With input from agencies)