Former US president Donald Trump says a terrorist attack at Kabul airport that killed at least 13 US servicemen was "the most embarrassing thing that's ever happened to our country".
Twin explosions that erupted outside Hamid Karzai International Airport killed dozens, including at least 13 US servicemen as well as many civilians who had gathered in the hopes of being evacuated from Afghanistan, which is now under the control of the Taliban.
Islamic State claimed responsibility for the attack.
US President Joe Biden has vowed to "hunt down" those responsible.
The Trump administration committed the United States to a full withdrawal from Afghanistan in a February 2020 deal with the Taliban.
Trump said the Biden administration had "botched the plan" for the withdrawal and the military should have been the last to leave but Biden took them out first, which was the "dumbest move anybody's ever made".
"I hear General (Kenneth) McKenzie say that the Taliban is going to protect us. The Taliban is the enemy," Trump told Fox News programme Hannity.
"Our country has never seen stupidity like this."
The outer perimeter of access to the airport is controlled by the Taliban, and the airport gates are managed under heavy security by US Marines and other troops.
Trump said US forces could have "left with safety".
"We could have taken everybody with us that we wanted, all of the great American citizens and people that helped us, whether it's interpreters or others," he said.
"We wouldn't have had a rush because the Taliban was not going anywhere, we had them totally under control.
"Every time we saw movement we would hit with a F/A-18 (combat jet) and the movement stopped."
Trump said he would have kept Bagram Airfield open — formerly the largest US military base in Afghanistan — as it was near China and Iran.
The airfield fell to the Taliban on August 15 after Afghanistan government forces surrendered, leaving people to evacuate from Kabul airport instead.
"We look like fools all over the world," Trump said.
"We're weak, we're pathetic.
"We're being led by people that have no idea what they're doing."
Biden has defended the withdrawal and insisted it was not a mistake to rely on the Taliban for help securing Kabul airport.
Asked by a reporter if he bore any responsibility for the death of the US service members killed, Biden said: "I bear responsibility fundamentally for all that's happened of late".
Biden has said the evacuation effort would proceed and end on schedule at the end of the month.
Several Republican politicians said Biden should resign or be impeached.
"Joe Biden is responsible," Senator Josh Hawley, of Missouri, said.
"It is now clear beyond all doubt that he has neither the capacity nor the will to lead. He must resign."
Representative Elise Stefanik, the third-ranking Republican in the House, tweeted that "Joe Biden has blood on his hands".
"The buck stops with the President of the United States," Stefanik said.
"This horrific national security and humanitarian disaster is solely the result of Joe Biden's weak and incompetent leadership. He is unfit to be Commander-in-Chief."
However, Illinois Republican congressman Adam Kinzinger, a former military officer, said both Republicans and Democrats were responsible for the current situation.
Kinzinger told CNN Trump had set up a deal "that would make Neville Chamberlain blush" but Biden had chosen not to reverse the deal and "owns this decision as much as Donald Trump, and the execution".