KABUL  - A Taliban suicide car bomber on Tuesday targeted staff at Afghanistan’s top court, killing 15 civilians and wounding 40 others in the second attack in two days in the heavily fortified capital, police said.

Women and children were among those killed and injured in the powerful explosion at the entrance to the Supreme Court, near the US embassy as buses waited to take court staff home at the end of the working day, officials said.

The Taliban claimed responsibility and threatened further attacks on the judiciary if it continued to sentence to death members of its militia.

The bomber struck at around 4:00 pm (1130 GMT) in the crowded area, close to a block of residential flats home to middle-class Afghans. General Mohammad Zahir, head of Kabul criminal investigations, said the bomber rammed one of the buses carrying Supreme Court staff. “A suicide bomb hit at the back of a coaster causing lots of civilian casualties, dead and wounded,” Zahir told AFP.

“The most precise and updated toll is 15 killed and 40 wounded,” he said.

He earlier said that at least two women were among the dead and children were also among the casualties. “Most of the casualties are Supreme Court employees,” he added.

An AFP photographer saw human flesh and dead bodies lying on the ground as police picked their way through the debris, the wreckage of a car and two badly damaged buses on the main road leading to the airport.

A couple of legs and part of a body were stuck to the back of one bus. Civilian volunteers who happened to be in the area where helping to evacuate the wounded, soaked in blood, by foot, on shoulder, dragged and by handcart.

The Taliban, the militia that is stepping up an 11-year insurgency against the Western-backed Afghan government as NATO troops prepare to withdraw next year, claimed responsibility for the attack.

In a statement, it said it had punished judges for “justifying the invading infidels” in sentencing to death Taliban prisoners held by the Afghan government.

“Today’s attack was a warning that should they (judges) continue to give tyrannical verdicts and intimidate (our) countrymen, then the mujahideen will not tolerate it and condemn them to death” said a copy of the statement seen by AFP.

In April, Taliban militants also stormed a court in the western town of Farah, killing at least 44 people in a bid to free insurgents standing trial.

Tuesday’s attack was the deadliest in Kabul since May 16 when a suicide car bomb struck a foreign military convoy, killing 15 people including five Americans.

Earlier Tuesday, the UN representative in Afghanistan said the Taliban have indicated that they are willing to discuss how to reduce civilian casualties.

Jan Kubis said the militants had agreed to hold talks with the UN and discuss the issue of civilian deaths, which rose by 24 per cent in the first half of 2013 compared to last year. “I can confirm that we sent publicly and also through our channels a signal of our willingness to discuss with Taliban issues of human rights... civilian casualties and how to reduce them,” he told reporters.

“I can confirm that we received signals about their willingness and readiness to discuss these issues with us. I welcome this,” he added.

He said the UN had registered 2,499 civilian casualties between January and June, attributing 74 percent to anti-government forces and nine percent to pro-government forces.

Children accounted for 21 per cent of all civilians killed and wounded. Casualties caused by makeshift bombs called IEDs - the Taliban’s weapon of choice— had risen 41 per cent. The Taliban were brought down in Kabul in 2001 by US-led troops for sheltering the Al-Qaeda militants behind the 9/11 attacks.

On Monday seven Taliban insurgents were killed after launching a gun and grenade attack on military buildings near the airport’s perimeter fence.

The response from Afghan security forces to that assault was widely praised as a sign of their growing professionalism, as they take over responsibility from 100,000 US-led foreign combat troops who will pull out by the end of next year.

On May 24 Taliban militants launched a coordinated suicide and gun assault on a compound in Kabul of the International Organization for Migration.

Meanwhile, Taliban insurgents announced Tuesday they have released a Kyrgyz hostage they seized in April after a helicopter crash-landing in a mountainous region south of Kabul.

The militants abducted the Kyrgyz man together with eight Turkish nationals, a Russian and an Afghan interpreter on April 21 after their helicopter made a hard landing in Logar province.

Taliban spokesman Zabihullah Mujahid, speaking to AFP by phone from an unknown location, said the hostage was freed as a goodwill gesture to the Kyrgyz government. The militants had earlier freed the Turkish nationals following the largest abduction of foreigners in Afghanistan in almost six years, highlighting the country’s continuing insecurity as NATO combat troops prepare to pull out next year.

A Russian and an Afghan interpreter are still being held, the spokesman said, adding that the men were being investigated.

Mujahid said the Kyrgyz national was freed “as (an) Islamic and humanitarian gesture of respect to his Islamic country”.

Asked why the Afghan national had not been freed, the rebel spokesman said he was being investigated for “possible ties with intelligence agencies”, but added that the rebel group would not execute him. Turkey, one of only two Muslim-majority members of NATO, has around 1,800 soldiers serving with the US-led military coalition, but they do not take part in combat operations.

Kyrgyzstan has no military presence in Afghanistan.