"My view of what happened in Afghanistan with Biden is he paved the way for another 9/11," Graham said in an interview with Fox News on Sunday.
The Senator warned that there is a rise of extremism and terrorism Afghanistan, a "lethal cocktail," which could result in an attack in the United States "in the next six months without warning."
Graham accused the Biden administration of "political whitewash" and of downplaying the risky consequences of the Afghanistan withdrawal.
"When the Biden administration tells you there are no terrorists in Afghanistan, they are lying," Graham said.
Earlier this month, US Secretary of State Antony Blinken said that the rapid fall of Kabul in 2021 took the United States by surprise and showed deficiencies in the US State Department's preparedness for the worst-case scenario in Afghanistan.