KABUL: A bomb exploded in the parking lot of Afghanistan's Ministry of Justice on Tuesday, killing at least five people and wounding dozens as civil servants were leaving work for the day, officials said.

The Taliban claimed responsibility for the attack and vowed to kill more “slave” judges. Taliban spokesman Zabihullah Mujahid made the statement in an email to journalists a few hours after the car bomb exploded.

Ministry of Interior spokesman Sediq Sediqqi confirmed the deaths of five by telephone, while Mohammad Ismail Kawusi, a spokesman for the Ministry of Public Health, said 42 wounded people had been admitted to three hospitals in Kabul. He said the number could climb.

This is the fifth major attack in Kabul in just over two weeks, and the third to target employees of the justice system, coinciding with the Afghan Taliban's spring offensive, "Operation Azm", across the country.

Sirens could be heard in the minutes after the blast as rescuers and police rushed to the scene.

“We only can confirm that there was an explosion in the Ministry of Justice parking area,” Ebadullah Karimi, a spokesman for Kabul police chief, told Reuters.

Another police official said a car packed with explosives detonated late in the afternoon but had no other information.

The huge explosion sent a plume of black smoke billowing above the city and was strong enough to rattle windows several kilometres away in Kabul's diplomatic district.

No one immediately claimed the bombing, but the Taliban have already attacked employees of Afghanistan's justice system this month, twice slamming car bombs into buses carrying employees of the attorney general's office.

At least four people were killed in the two previous attacks.

On Sunday, a suicide car bomber rammed a convoy of the European Union Police Mission in Afghanistan, killing two Afghan civilians and a British security contractor.

Four days earlier, gunmen opened fire inside a Kabul guesthouse popular with foreigners and killed 14 people, including two Pakistanis.

Read more: Two Pakistanis among 14 killed in Taliban siege of Kabul guesthouse

Taliban spring offensive

The Afghan Taliban's annual “spring offensive” began in April 2015, with the militant outfit vowing nationwide attacks in what is expected to be the bloodiest fighting season in a decade as Nato forces pull back from the frontlines.

This year’s offensive marks the first fighting season in which Afghan forces will battle the insurgents without the full support of US-led foreign combat troops.

“The Islamic Emirate is going to launch the spring operations under the inspirational name of ‘Azm’ (Determination) at 5 am on 24th April 2015,” the Taliban said in a statement in April

“The main targets of these operations... will be the foreign occupiers, especially their permanent military bases... officials of the stooge regime, their military constellations, especially their intelligence, interior ministry and defence ministry officials.”

Prime Minister Nawaz Sharif in a visit to Kabul in May pledged his support in the Afghan government's fight against the Taliban, saying that Pakistan had the highest stake in a peaceful and stable Afghanistan.

"We agreed that peace and stability in the region will remain elusive until the menace of terrorism afflicting the region is comprehensively addressed."

Following Nawaz's visit, Pakistan’s premier intelligence agency Inter-Services Intelligence (ISI) and the Afghan intelligence outfit National Directorate of Security (NDS) some time last week in Kabul signed a path-breaking accord for cooperation which is aimed at bolstering the fight against terrorism.

Inter-Service Public Relations spokesperson, Maj Gen Asim Bajwa tweeted: “MoU signed by ISI and NDS includes intelligence sharing, complementary and coordinated intel operations on respective sides,” while President Ashraf Ghani’s spokesman Ajmal Abidy, was quoted by Afghanistan’s ToloNews, as saying: “The focus of this agreement is mostly on jointly fighting terrorism.”

Read more: ISI, Afghan intelligence in landmark deal