Karzai called for the Loya Jirga, a national consultative assembly of tribal elders, which will begin meeting Thursday to discuss the proposal. Some 3,000 elders and influential figures will debate the Bilateral Security Agreement.
Without its approval, Afghanistan likely will refuse to sign the agreement. If the Loya Jirga does approve it, the agreement still requires final approval from parliament, Karzai said.
US officials refused to comment on the draft, describing the effort as an ongoing diplomatic process. Karzai provided few details regarding how and when the draft was finalised, but said there still remain "differences" between Washington and Kabul on the deal.
Negotiations have been protracted and often acrimonious. In the end it took a surprise visit to Afghanistan in October by US Secretary of State John Kerry to produce the outlines of a deal.
Earlier, two senior US officials told The Associated Press that Afghanistan had sought specific security guarantees, particularly against cross-border incursions by insurgents from neighbouring Pakistan. Washington is cautious about any commitments that could lead to a conflict with Pakistan. The officials spoke on condition of anonymity because of the deal was still being negotiated.
Karzai described a laborious negotiation process that sometimes came down to fine details of phrasing.
"There was one word that we didn't want in the agreement but (the US) wanted it and in the end they agreed to not use that word," he said, without identifying the offending word.
Karzai did not say what the draft said regarding US service members' immunity from prosecution in an Afghan court. They could still face prosecution in a US court.
The sweeping document incorporates the usual Status of Forces Protection Agreement, which the US signs with every country where its troops are stationed, along with a wide range of other clauses. It covers everything from customs duties on goods the US imports for its troops and development projects to the question of whether a US service member could be prosecuted for criminal offences in an Afghan court.
Still this key American demand has been a sore point in Afghanistan. Many are still angry over incidents including the February 2012 accidental burning of hundreds of copies of the Islamic holy book, the Quran, a March 2012 shooting spree by a US soldier in southern Afghanistan that killed 16 people, and unintended civilian deaths from US bombs.
Still, the audacity of Saturday's daylight bombing, just 200 metres from the site of the Loya Jirga, was a stark reminder of militants' striking power in the country. It also seemed to bolster arguments of those who favour the security agreement and a continued presence of international forces in Afghanistan.
"I believe that without this document, Afghanistan would again be isolated and alone," National Security Adviser Rangin Dadfar Spanta told parliament Saturday.
Spanta warned that without a security agreement with the US, Afghanistan would be vulnerable to interference from its neighbours. Afghan officials routinely accuse Pakistan of interfering in its internal affairs and harbouring insurgents on its soil.
A "no" vote from the Jirga likely will scuttle the agreement and leave Afghanistan without any US forces after the end of 2014. With the agreement, the residual force of about 10,000 that is expected to remain behind would mostly train and mentor Afghanistan's National Security Force. A small group of US Special Forces also are expected to stay in Afghanistan to hunt down al-Qaeda fighters and carry out counter-terrorism activities.
In his comments Saturday, Karzai didn't come out and endorse the agreement. He only urged participants of the coming Loya Jirga to carefully read it.
"They should think about the prosperity and stability of today and tomorrow in Afghanistan. And whatever decision they are making they should think about the future of Afghanistan," he said.
- AP