KABUL -- Police say a bomb has exploded near the venue where thousands of influential Afghan figures will gather next week to debate a key U.S.-Afghan security pact.
At least 10 people were killed and 13 others injured in the blast on the western edge of Kabul.
The Taliban later said it was responsible.
The attack came just hours after President Hamid Karzai told reporters the final draft of the security agreement had been completed.
Officials in Kabul described the attack as a "suicide car bombing that inflicted casualties."
Interior Ministry spokesman Siddiq Siddiqi told RFE/RL that there were several causalities among both civilians and security officers, but he could not immediately give exact numbers.
Siddiqi said security services "have had information that a terrorist attack targeting the area was being plotted."
"We have been taking measures to find out people behind the plot but the attack was carried out before we could prevent it," Siddiqi added.
"Police were following an explosive-laden vehicle but unfortunately the suicide driver detonated the vehicle near a security-forces checkpoint."
Despite the attack, Siddiqi expressed confidence that Afghan security forces were "capable of providing security for the upcoming Loya Jirga."
About 3,000 tribal elders and other prominent figures from across Afghanistan are expected to gather for the Loya Jirga, or Grand Council, on November 21 to discuss a U.S.-Afghan agreement that would allow U.S. troops to remain in Afghanistan after the withdrawal of international forces in 2014.
Afghan authorities have stepped up security measures in the area in recent weeks. Hundreds of soldiers and security officers have been deployed around the compound of the Kabul Polytechnic University, where the Loya Jirga will be he held.
Karzai Urges Opponents To Attend
The Taliban has warned the Loya Jirga members not to participate in the gathering.
Earlier on November 16, Karzai said that the Taliban, including former Prime Minister Gulbuddin Hekmatyar's Hizb-e Islami (Party of Islam) militant group, had the right to participate in the Loya Jirga.
"Concerning the participation of the Taliban and Hekmatyar's Hizb-e Islami -- we wish for their participation. They are people of Afghanistan and have the right to participate in such gatherings. They owe it to Afghanistan and Afghanistan owes it to them," Karzai said.
"But they owe it more to Afghanistan to come and have their say in such an extremely important national issue, whether they are for the agreement or against it."
Hizb-e Islami has said it is "against the convening of such a loya jirga."
Karzai pointed out that there are still disagreements between Kabul and Washington over the final content of the security agreement.
He said that without approval of the Loya Jirga, Afghanistan will likely refuse to sign the so-called Bilateral Security Agreement.
The agreement would allow U.S. authorities to maintain legal jurisdiction over those U.S. troops who remain in Afghanistan after the 2014 drawdown of foreign forces.
With reporting by Reuters and AP