Top US general Mark Millie has warned that al-Qaeda terrorists in Afghanistan could become a threat to the United States within 12 months.
General Millay says it will now be difficult to save Americans from violent attacks from Afghanistan.
"The Taliban were and are an extremist organization and they have not severed ties with al-Qaeda," he said.
The general met and the defense minister faced tough questions
The top US general and Secretary of Defense are facing tough questions in the US Congress over the withdrawal of US troops from Afghanistan last month.
The rapid advance of the Taliban in Kabul led to the overthrow of the government there.
Senator and committee leader Jack Reid said US lawmakers wanted to know whether the United States was "unaware of the signs" of a government collapse in Kabul.
The United States has said it will focus on counterterrorism targets.
The hearing by the Senate Armed Services Committee comes just weeks after an emergency evacuation at Kabul Airport, where foreign powers continue to try to repatriate their citizens and appeal to thousands of desperate Afghans to rescue themselves. Keep doing
During the evacuation operation, a suicide attack on the gate of Kabul Airport on August 26 killed 182 people. The dead included 169 Afghan civilians and 13 American soldiers.
The committee's proceedings began on Tuesday, when Secretary of Defense Lloyd Austin and then General Mark Millie testified.
Another US general, Kenneth McKenzie, will also appear before the committee. As head of US Central Command, General Mackenzie also oversaw the evacuation operation from Afghanistan.
Immediately after the 9/11 attacks, US forces entered Afghanistan in late 2001. By the time US troops withdrew from Afghanistan, the United States had spent about 5 985 billion on the Afghan war. Tens of thousands of troops were stationed there during the war, and in 2011 the largest number of US troops was stationed in Afghanistan at 110,000.
In the weeks leading up to the Taliban's takeover of Kabul and the August 31 withdrawal deadline, the United States withdrew 4,000 troops from Afghanistan. Meanwhile, the United States also ensured the evacuation of more than 50,000 Afghan refugees from Kabul during the air operation.
