Pakistani police officer gather at the site of bombing in Karachi, Pakistan, Thursday, Feb. 13, 2014. A bomb attack killed at least some police officers and wounded dozens others in Pakistan's southern city of Karachi on Thursday. A van exploded after hitting a bus the officers boarded moments after it had left a training school in what appeared to be a suicide attack, said police officer Rao Anwaar. (AP Photo/Shakil Adil)

Islamabad - Eleven people including a judge were killed Monday in a gun and suicide bomb attack on a court complex in Islamabad, a rare strike at the heart of the heavily-guarded Pakistani capital.

Pakistan has been in the grip of a bloody homegrown Taliban insurgency since 2007 but there have been very few attacks in recent years in the capital.

The Pakistani Taliban denied any connection to the assault, which came two days after the militants announced a month-long ceasefire aimed at restarting stalled peace talks with the government.

More than 110 people have now been killed in militant attacks since Prime Minister Nawaz Sharif announced the talks in late January, leading some observers to question the value of the process.

A spokesman for the Ahrar-ul-Hind militant group, which recently split from the main Tehreek-e-Taliban Pakistan (TTP) umbrella group, claimed Monday's attack.

There have been reports of disagreement over talks within the TTP, and analysts have voiced fears that any splintering of the movement would render the peace process useless.

But the radical cleric leading the TTP's team for talks insisted the dialogue could still succeed.

Islamabad police chief Sikandar Hayat said the attack began around 9:00 am (0400 GMT) with gunfire followed by two suicide blasts, which killed 11 people and wounded 29.

It was the first suicide attack in Islamabad since June 2011 and the deadliest in the city since a huge truck bomb at the Marriott Hotel killed 60 people in September 2008.

Blood, human remains and spent bullet casings littered the court complex in the prosperous F-8 sector of the city which is popular with foreigners, an AFP reporter said.

The dead included Judge Rafaqat Awan, who last year rejected a petition to prosecute former military ruler Pervez Musharraf over a deadly raid on Islamabad's radical Red Mosque in 2007.

The case against Musharraf later went ahead and it was not clear whether Awan was the intended target of Monday's attack.

Eyewitnesses described the gunmen firing indiscriminately in the warren of narrow, dusty streets housing court chambers and lawyers' offices.

Lawyer Murad Ali Shah described the dramatic moment the carnage began.

“At 9:00 am armed men surrounded the court compound. They entered the chamber and started firing,” he told AFP, adding that he had helped recover several bodies.

“The attackers were armed with Kalashnikovs and hand grenades.”

On Sunday the Pakistani government announced it was halting air strikes against suspected Taliban hideouts in the restive tribal areas along the Afghan border in response to the ceasefire the militants called on Saturday.

The main TTP spokesman said Monday the group was committed to the ceasefire and would stick to it “strictly”.

Asad Mansoor, spokesman for Ahrar-ul-Hind, said it staged Monday's attack.

“We claim responsibility for the attack, we are an independent group and have no links with TTP,” he told AFP.

“We were a part of TTP earlier but now we operate independently.”

The government began peace talks with the TTP last month but the dialogue broke down after militants killed 23 kidnapped soldiers.

The military responded with a series of air strikes in the tribal areas that killed more than 100 insurgents, according to security officials.

Maulana Sami-ul-Haq, the head of the TTP negotiating team, condemned the court attack and urged the government to stick with the talks.

“I am confident that our dialogue will be successful as we have already started moving towards our destination,” he told reporters.

Security analyst Talat Masood said the continued violence was in danger of making the talks process meaningless.

“It only goes to show the multiplicity of various militant organisations operating in Pakistan,” he told AFP.

“It is not just TTP but several other groups, and the government is focusing in a very small area. It should look at the broader picture and not just one group.”

The Taliban's ceasefire announcement on Saturday was met with scepticism by analysts, who said it may have been a tactic to allow them to regroup after they had suffered heavy losses in air strikes.

The government has struck peace agreements with the Pakistani Taliban several times in the past but they have failed to yield lasting results.

The umbrella militant group emerged in response to the raid on the Red Mosque in 2007, but Islamist violence in the country began to surge in 2004 following the army's deployment in the tribal areas.