KABUL - At least 12 people including three children were killed and 20 others wounded when a car bomb exploded near the Kabul Airport early Wednesday, Afghan officials said.

The target of the blast appeared to be an armoured vehicle belonging to GardaWorld, a Canadian security company, and at least four of the wounded were foreigners, said Nasrat Rahimi, a spokesman for the Ministry of Interior. He did not immediately know the nationalities of the wounded and GardaWorld did not immediately respond to a request for comment.

The powerful blast shook Kabul during rush hour, smashing windows of houses and shops nearby, residents said.

Also on Wednesday, the election commission said the long awaited results of the Sept. 28 presidential election were still not ready due to technical issues and would not be announced on Thursday as had been planned. The announcement of the results has been repeatedly postponed and on Sunday main opposition figure Abdullah Abdullah withdrew his observers from the recount process citing irregularities.

Foreigners among 20 wounded

The suicide bombing was the first major attack on the Afghan capital after about a month of relative calm, and it came only one day after President Ashraf Ghani said he would release three high-profile Taliban commanders from prison, a major concession he said he hoped would jump-start talks and lead to the release of hostages, including two foreigners, one American and one Australian, kidnapped by the Taliban in 2016.

The three Taliban prisoners, Mali Khan, Hafiz Rashid and Anas Haqqani, belong to the Haqqani network, a wing of the Taliban behind the abductions of a number of high-profile foreigners in recent years, including US soldier Bowe Bergdahl, who was held for five years.

Haqqani is the son of the Haqqani network’s founder. His older brother is the deputy leader of the Taliban.

No group has claimed responsibility for Wednesday’s attack.

It was not immediately clear if the Taliban commanders Ghani said he planned to release were still in prison Wednesday.

A security official told The Washington Post on Tuesday that the three could be transferred to Qatar, where the group has an office, as soon as Tuesday evening. He said the two hostages, US citizen Kevin King, 63, and Australian Timothy Weeks, 50, had not yet been released, but that the Afghan government hoped that transferring the Taliban commanders would lead to an exchange.

The pair, who were teaching English at the American University of Afghanistan, were kidnapped at gunpoint close to the university campus in August 2016. The Taliban has since warned that King’s health was rapidly deteriorating. In his remarks Tuesday, Ghani said the Taliban release was a “humanitarian gesture,” citing concerns that the hostages held by the Taliban were unwell.