At least seven people were killed and 10 wounded, including four foreigners, when a minivan packed with explosives detonated during Kabul’s morning rush hour on Wednesday, an interior ministry spokesman said.

The spokesman, Nasrat Rahimi, said the bomb – targeting an SUV belonging to private Canadian security company GardaWorld – had gone off in a neighbourhood near the interior ministry and north of Kabul airport.

“As a result, seven of our people were killed and 10, including four foreign members of the security company, were wounded,” he said, describing the dead as Afghan civilians.

He did not confirm the nationalities of the foreigners involved.

Interior Minister Massoud Andarabi said that one of those killed was a 13-year-old child heading to school.

“The enemies of our people should know that our people are determined for peace, nothing can stop them from achieving peace,” he said.

A source at the interior ministry said the blast was detonated by a suicide bomber in the vehicle, which officials had earlier described as a car.

There was no immediate claim of responsibility. Both the Taliban and the Islamic State group are active in the city, which is one of the deadliest places in the war-torn country for civilians.

The blast came a day after Afghan President Ashraf Ghani announced that Kabul would release three high-ranking Taliban prisoners in an apparent prisoner swap with Western hostages who were kidnapped in 2016.

The three Taliban prisoners include Anas Haqqani, who was seized in 2014 and whose older brother is the deputy Taliban leader and head of the Haqqani network, a notorious Taliban affiliate.

Ghani did not specify the fate of the Western hostages – an Australian and an American, both professors at the American University in Kabul – and it was not clear when or where they would finally be freed.

The two, American Kevin King and Australian Timothy Weeks, were kidnapped in August 2016 from the heart of Kabul.

They later appeared looking haggard in a Taliban hostage video, with the insurgents going on to say that King was in poor health.

Ghani noted in his speech that “their health has been deteriorating while in the custody of the terrorists”.

He also did not state when or where the Taliban prisoners would be freed.

The Taliban spokesman Zabihullah Mujahid said on Wednesday that he could not confirm anything about the swap yet.

“When our captives reach their destination, the American University professors will be released,” he said.

Ghani said that he hoped the decision would help “pave the way” for the start of unofficial direct talks between his government and the Taliban, who have long refused to negotiate with the administration in Kabul.