ISLAMABAD - A car bomb explosion in the Afghan capital of Kabul Wednesday killed at least 12 people and wounded about 20 others, including children.

Interior Ministry spokesman Nasrat Rahimi tweeted the early morning blast targeted a foreign private security company vehicle. He said four foreign employees of the company were among those injured but gave no further details.

There were no immediate claims of responsibility for the bombing, which came after days of a lull in violence in Kabul.

Taliban insurgents and militants linked to the Afghan branch of Islamic State often claim credit for plotting such attacks.

Wednesday’s violence comes a day after Afghan President Ashraf Ghani freed three high-profile Taliban prisoners in exchange for two Western hostages, an American and an Australian.

The two foreigners were teaching at Kabul’s American University of Afghanistan before they were kidnapped at gunpoint near the campus in August 2016.

Meanwhile, the country's Independent Election Commission (IEC) Wednesday postponed for a second time the announcement of preliminary results from the Afghan presidential polls.

The commission was due to release first results on November 14 after failing to meet the original deadline of October 19. But the IEC spokesman Abdul Aziz Ibrahimi said the results would not be announced on Thursday “until the technical issues are addressed.”

Incumbent President Ghani’s main challenger Chief Executive Abdullah Abdullah earlier this week withdrew his team of observers from the vote recounting process, demanding IEC declare as invalid around 300,000 “fraud-marked” votes if he were to accept the results.