A suicide bomber rammed his car into an Afghan army vehicle providing security for a compound where Afghanistan’s political and tribal elites are due to gather next week to debate a security pact with the US.

Yesterday’s attack took place just hours after President Hamid Karzai called on the Taliban to take part in the Loya Jirga assembly that convenes on Thursday to decide whether to allow some US troops to stay in Afghanistan after 2014.

At least 10 people were killed and 22 wounded in the blast, said Sediq Sediqqi, an Interior Ministry spokesman. He said the casualties were a mix of soldiers and civilians.

The blast occurred shortly after 3pm, fewer than 100 metres from a huge tent where more than 2,000 prominent Afghans are due to gather, a Reuters witness said.

No one immediately claimed responsibility for the attack.

One man fleeing the bombing, Mohammad Amin, looked dazed as he described to Reuters seeing a white Totoya Corolla vehicle speed towards a police checkpoint and then explode.

Covered in blood and dust, he said he was standing across the street behind his parked car when the blast occurred.

“Thank God my car protected me because it was so close. My ears are still ringing,” Amin said. A Reuters reporter saw at least six wounded people, as well as a large unchecked fire and numerous smashed cars.

A Kabul police spokesman, Hashmat Stanekzai, said earlier there were at least 15 dead and wounded as a result of the attack, but could not immediately provide more detail.

A loya jirga is a traditional Afghan meeting convened to debate matters of national importance and includes thousands of tribal elders, politicians and other elites. For almost a year, Washington and Kabul have been seeking to conclude a Bilateral Security Agreement.