The US intelligence community has assessed that Islamic State in Afghanistan could have the capability to attack the United States in as little as six months, and has the intention to do so, a senior Pentagon official told Congress on Tuesday. The remarks by Colin Kahl, under secretary of defence for policy, are the latest reminder that Afghanistan could still pose serious national security concerns for the United States even after it ended its two-decade-old war in defeat in August. The Taliban, which won the war, are enemies of Isis and have seen its attempts to impose law and order after the US pull-out thwarted by suicide bombings and other attacks claimed by Isis. They include bombings targeting the minority Shiite sect and even an Isis beheading of a member of a Taliban militia force in the eastern city of Jalalabad. 47 killed, 70 injured in suicide bombing at Afghanistan mosque In testimony before the Senate Armed Services Committee, Kahl said it was still unclear whether the Taliban has the ability to fight Islamic State effectively following the US withdrawal in August. The United States fought the Taliban as well as striking groups like Isis and al-Qaeda. “It is our assessment that the Taliban and Isis-K are mortal enemies. So the Taliban is highly motivated to go after Isis-K. Their ability to do so, I think, is to be determined,” Kahl said, using an acronym for Isis in Afghanistan. Kahl estimated Isis had a “cadre of a few thousand” fighters. Acting Foreign Minister Amir Khan Muttaqi of the new Taliban government has said the threat from Isis militants will be addressed. He also said Afghanistan would not become a base for attacks on other countries. Kahl suggested al-Qaeda in Afghanistan posed a more complex problem, given its ties to the Taliban. It was those ties that triggered the US military intervention in Afghanistan in 2001 following al-Qaeda’s September 11 attacks on New York and Washington. The Taliban had harboured al-Qaeda leaders. Kahl said it could take al-Qaeda “a year or two” to regenerate the capability to carry out attacks outside Afghanistan against the United States. US eyes air strikes on al-Qaeda in Afghanistan, thousands of miles from nearest base US President Joe Biden , whose supervision of the chaotic end to the war last summer has damaged his approval ratings, has said the United States will continue to be vigilant against threats emanating from Afghanistan by carrying out intelligence-gathering operations in the country that would identify threats from groups like al-Qaeda and Isis. Kahl said the goal was to disrupt those groups so that Isis and al-Qaeda don’t become capable of striking the United States. “We need to be vigilant in disrupting that,” he said. Still, US officials privately warn that identifying and disrupting groups like al-Qaeda and Isis is extremely difficult without any troops in the country. Drones capable of striking Isis and al-Qaeda targets are being flown in from the Gulf. Kahl said the United States did not yet have any agreement with countries neighbouring Afghanistan to host troops for counterterrorism efforts.