"The senior leadership of Al-Qaida remains present in Afghanistan, as well as hundreds of armed operatives, Al-Qaida in the Indian Subcontinent, and groups of foreign terrorist fighters aligned with the Taliban," the UN report said, estimating that some 400 to 600 armed al Qaeda operatives are currently in Afghanistan.

"The Taliban regularly consulted with Al-Qaida during negotiations with the United States and offered guarantees that it would honour their historical ties," the report added.

The report was sent to the UN Security Council late last month and was produced by the UN's Analytical Support and Sanctions Monitoring Team.