Afghan security forces killed an attempted suicide bomber in the capital on Monday near the location of a major meeting of tribal elders and political leaders set to begin in two days, a spokesman for the interior ministry said.

President Hamid Karzai has called the loya jirga, or the traditional assembly, to discuss among other issues a possible U.S. military presence after 2014 when foreign combat troops leave.

A suicide bomber who was carrying a bag of explosives was shot dead near (the loya jirga tent), Sediq Sediqqi said. He was killed before he could carry out his mission.

The four-day gathering in Kabul, due to start on Wednesday, will bring together more than 2,000 politicians, tribal elders, community leaders, businessmen and civil society representatives from across the country.

Last month, the Afghan Taliban said it would target participants in the assembly which will deliberate upon the possibility of long-term U.S. military bases in Afghanistan.

The Taliban have long fought against presence of foreign troops in the country.

On Sunday, the Taliban said they had obtained a copy of the detailed security plan for the loya jirga, a claim the NATO-led International Security Assistance Force (ISAF), responsible for security in much of the country, dismissed as fabricated propaganda.

Lutfullah Mashal, a spokesman for the National Directorate of Security, told journalists the alleged security plan was not genuine, and was instead a Taliban reaction to successful security measures which had prevented insurgents from bringing explosives into Kabul.

Earlier on Monday, National Security Advisor to Karzai, Rangan Spanta, said an investigation was underway, but did not rule out the possibility the document may have been genuine.

Afghan security forces are investigating that and it is a matter of concern and regret for us, he told parliament.

During last year's assembly in June, insurgents fired at least four rockets at a the tent in which it was held. They all fell short, but the attack was followed by a commando raid by three insurgents wearing suicide vests.

The country's then-interior minister and head of intelligence resigned over lapses that led to the attack.

The jirga is a consultative rather than a lawmaking body, and its recommendations will go to the Afghan parliament for approval.

Safiullah Zeer, an organiser of the media and cultural department of this week's meeting, said that delegates would talk about an overall strategic partnership agreement with the United States.

(Reporting by Mohammad Ibrahim, Mirwais Harooni, Sayed Hassib and Jan Harvey; Writing by Daniel Magnowski; Editing by Sanjeev Miglani)