US Intelligence assessments paint an increasingly bleak picture of the Taliban's quickening advance across Afghanistan and the potential threat it poses to the capital of Kabul, warning the militant group could soon have a stranglehold on much of the country in the wake of the US withdrawal of troops, multiple sources briefed on the intelligence tell CNN, the latter reported.

The Taliban advance is "accelerating at an accelerating pace," said a congressional source with knowledge of the intelligence, echoing concerns raised by other officials who have acknowledged the security situation is deteriorating even more rapidly than previous assessments have indicated.

While multiple sources familiar with recent US intelligence assessments argue Kabul is not at imminent risk of a takeover, thanks in part to the threat of US airstrikes and the size of the Taliban force.

US intelligence agencies currently believe that the Taliban could effectively choke off the Afghan government's import supply if they choose to do so and will likely encircle much of the country in the near future.

In addition, these sources say Taliban fighters could potentially move on the capital once they are confident the outcome would be successful.