At least 11 people were killed and dozens wounded in an attack on a Pakistan court complex in a busy shopping area on Monday. (Reuters)

Two suicide bombers armed with grenades stormed Islamabad’s district court complex Monday morning, killing 11 people in the deadliest terrorist attack in Pakistan’s capital in several years.

The attack occurred at 8:30 a.m. when the men, described by police as “professional terrorists,” entered the complex and began firing assault rifles as they lobbed hand grenades at judges, lawyers and residents gathered for civil-court proceedings.

Witnesses said the men fired indiscriminately, creating panic in one of Pakistan’s safest and most heavily guarded cities.

“Everyone was running to save their life, and it was a horrible scene,” said M. Yaseen, a 46-year-old trader who had gone to the courthouse to process some paperwork. “I felt like I was watching a movie and this was not real.”

The attack, which killed a district court judge, at least three lawyers and the chief constable, occurred less than 24 hours after Pakistan’s government announced that it had agreed to an unconditional one-month cease-fire with the Pakistani Taliban.

The cease-fire was supposed to head off a Pakistani military operation against militant strongholds in northwest Pakistan and allow for the resumption of preliminary peace talks between Prime Minister Nawaz Sharif’s government and Taliban representatives. Instead, Sharif and the Pakistani military are again being tested over how much bloodshed they are willing to accept in hopes of reaching a negotiated peace agreement.

The assault on the court complex lasted 45 minutes and ended only after the gunmen blew themselves up in front of a courtroom. According to police, at least 25 people were wounded in the attack. The dead included Rafaqat Awan, a prominent district court judge.

Shabir Hussain, 30, a lawyer, said he saw the gunmen shoot and kill Awan.

“They were very calm and composed and seemed to be well-trained militants,” Hussain said. “We heard people crying all around — lawyers lying injured on the ground with blood around them.”

Pakistani Taliban leaders quickly distanced themselves from the attack. But a former Taliban faction, known as Ahrar-ul-Hind, claimed that it had carried out the attack to show its displeasure with the peace process.

“Our fight will continue,” Asad Mansoor, a spokesman for Ahrar-ul-Hind, said in an interview. “We will carry on attacks on urban areas, police and markets until there is the complete imposition of sharia law.”

Just a few hours before the attack, Pakistan’s government announced that it was halting several weeks of airstrikes that targeted militants and foreign fighters near the border with Afghanistan and in Khyber Pakhtunkhwa province. The airstrikes began after a faction of the Taliban executed 23 Pakistani soldiers who had been held captive since 2010.

Pakistani officials and analysts had predicted that the airstrikes would be quickly followed up by a major military ground assault aimed at dislodging militants affiliated with the Pakistani Taliban, the Haqqani network and al-
Qaeda. But just when it appeared that a ground offensive could be imminent, the Pakistani Taliban announced Saturday that it wanted a one-month cease-fire with government forces.

However, with more than 40 militant groups thought to be operating in Pakistan, analysts say the government faces a daunting challenge in trying to secure the country through a negotiated settlement.

“There are forces who don’t want this process to proceed,” said Imtiaz Gul, a Pakistani security analyst.

In a report submitted to the National Assembly last week, the Interior Ministry said 900 people have been killed in more than 1,700 attacks across Pakistan in the past six months.

The bulk of the violence was focused in Baluchistan province, where Baluch separatists are waging an insurgency; against the government in Peshawar, the provincial capital of Khyber Pakhtunkhwa province; and in Karachi, Pakistan’s largest city.

Although there were numerous attacks in Islamabad from 2006 to 2009, including the 2008 bombing of the Marriott Hotel, which killed 56 people, Islamabad has been relatively secure in recent years. It is home to government ministries and foreign embassies, and Pakistani security officials, visible throughout the city, closely scrutinize the movements of Pakistanis who do not reside in the capital.

But security officials have been warning for weeks that Islamabad was vulnerable to attack. In an intelligence assessment made public last month, the Interior Ministry said Islamabad was “a very dangerous city” because numerous “sleeper cells” affiliated with the Taliban and al-Qaeda reside in the Pakistani capital.

Muhammad Binyamin, a police officer who witnessed Monday’s attack, said the operation was carried out by well-trained militants who were “very professional.”

Syed Imran Gardezi, a lawyer who was inside the court complex when the attack took place, said he saw “two guys with long, black beards with AK-47s in one hand and hand grenades” in the other walking through the complex.

“They were shooting everyone in sight,” Gardezi said. “I was running for my life.”

Shaiq Hussain, Haq Nawaz Khan and Aamir Iqbal contributed to this report.