KABUL - Afghan President Hamid Karzai on Saturday called on the Taliban and their allies to join an assembly on a security pact that could allow some US troops to stay in the country after 2014.

Around 2,500 tribal elders and civil leaders are expected to take part in an assembly known as a ‘loya jirga’ next Thursday, to decide whether to accept the draft Bilateral Security Agreement between Afghanistan and the US.

“We invite them, please come to this national jirga of Afghanistan, raise your voice, raise your objection... and share your views,” he told a news conference in Kabul.

The draft pact was hammered out in Kabul last month during a visit by US Secretary of State John Kerry. But he left without a final deal as Afghan President Hamid Karzai said only a jirga had the authority to decide the contentious issues.

These include a US demand to retain legal jurisdiction over its troops in Afghanistan, which would give them immunity from Afghan law. The request emerged as the main sticking point after Kerry’s visit.

The Taliban, whose government was toppled by a US-led invasion in 2001, has rejected the jirga and warned its members that they would be punished as ‘traitors’ if they endorsed the deal.

Hezb-e-Islami, a Taliban affiliate has also refused to send members to jirga calling it “legalising the US occupation”.

“This security agreement has supporters who support it without reasoning and also has oppositions who oppose it without reasoning,” Karzai said.

If the agreement is passed by both loya jirga and parliament, between 5,000 and 10,000 US troops would stay in Afghanistan to help fight Al-Qaeda remnants and train the national army.

Meanwhile, a suicide bomber detonated an explosives-packed car in Kabul on Saturday, killing at least six people near a compound where a security pact between Afghanistan and the US will be debated, officials said.

Another 22 were injured when the vehicle blew up about 150 metres from the giant tent which will on Thursday host a meeting of elders on the future of US troops in the country after a Nato coalition pulls out in 2014.

“Inital information shows that unfortunately four civilians, one police and one soldier have been killed in today’s attack,” Afghan interior ministry spokesman Sediq Sediqqi told AFP.

“Twenty-two more, the majority of whom are civilians, have been injured,” he added, noting that the toll may rise.

There has been no claim of responsiblity so far, but the assembly, known as a ‘Loya Jirga’, has been denounced by the Taliban who have warned their members not to participate.

“No doubt the enemy will try its best to target the jirga, but I can say with confidence that our security forces are on high alert and will foil the enemy’s desperate effort,” said Sediqqi.

According to a statement issued by the interior ministry, the bomber was being pursued by security forces shortly before the explosion.

“The attacker driving a vehicle had been identified and was being pursued by security forces. He detonated himself after police opened fire on his vehicle.”

Nasrullah, a witness, said: “I heard a big bang near the jirga site, and later saw ambulances carrying bloodied people. I saw at least three wounded in army uniforms.”

Earlier in the day, President Hamid Karzai had called on the Taliban and their allies to join the assembly, which is expected to include 2,500 tribal elders and civil leaders from around the country.

Washington had been pushing for the agreement to be signed by the end of October to allow the US-led Nato coalition to plan the withdrawal of its 75,000 combat troops by December 2014.

The collapse of a similar security agreement with Iraq in 2011 led to the US pulling all its troops out of the country, which is currently suffering its worst sectarian violence since 2008.