At least 12 people were killed and 66 others wounded in an explosion in Afghanistan’s capital Saturday, an Afghan Ministry of Public Health official said.

Four U.S. DynCorp employees were killed in a similar Kabul suicide attack in 2013.

The bombing appeared to catch the Taliban by surprise, as did some of the attacks two weeks earlier, and a spokesman, Zabihullah Mujahid, denied that the insurgents had anything to do with the attack.

U.S. Col. Brian Tribus, a North Atlantic Treaty Organisation spokesman, said the three contractors had been killed, without elaborating.

While no group has claimed responsibility for the bombing, the Taliban has increased attacks on government and North Atlantic Treaty Organisation infrastructure in Kabul since the U.S.-led mission in the country concluded after more than 13 years of war last year.

The assault struck close to the personal Shinozada hospital, the sound of the highly effective blast roaring all through the capital.

An Afghan man weeps as he runs at the site of a auto bomb blast in Kabul, Afghanistan August 22, 2015. “There were a lot of casualties”.

That evening, suicide attacks on a police academy and a base used by US special forces killed more than 30 police and security contractors, besides an American soldier.

Afghanistan’s chief executive officer, Abdullah Abdullah, who shares power with Ghani and has been critical of Pakistan’s record on fighting the Taliban, called the attack a war crime.

Without providing more details, the statement said “We are gathering further information”.

As per initial reports, officials say a suicide auto bomber targeted a foreigners’ convoy.

Saturday’s bomb is the latest in a wave of attacks unleashed on the Afghan capital since the announcement in late July of the death of the Taliban leader Mullah Omar.