Former US President Donald Trump has slammed his successor Joe Biden on his Afghan policy and expressed concerns that thousands of terrorists might have been flown out of Afghanistan as part of the evacuation process.

Biden surrendered Afghanistan to terrorists and left thousands of Americans for dead by pulling out the military before our citizens, Trump said in a statement on Tuesday.

"Now we are learning that out of the 26,000 people who have been evacuated, only 4,000 are Americans. You can be sure, the Taliban, who are now in complete control, didn't allow the best and brightest to board these evacuation flights.

"Instead, we can only imagine how many thousands of terrorists have been airlifted out of Afghanistan and into neighbourhoods around the world. What a terrible failure. NO VETTING. How many terrorists will Joe Biden bring to America? We don't know!" he said.

Meanwhile, Republican Congressman Mike Waltz, a veteran of the war in Afghanistan, introduced a resolution in the House of Representatives, condemning Biden's failure to heed the advice of military and intelligence advisors about the speed and nature of the Taliban offensive, failure to present a coherent counter-terrorism or evacuation plan to the American people, and the damage done to the US credibility as a result of the president's abandonment of America's Afghan allies.

The resolution was co-sponsored by Minority Leader Kevin McCarthy, Minority Whip Steve Scalise and Conference Chairwoman Elise Stefanik.

"President Biden has embarrassed the United States on the world stage and created the worst foreign policy blunder in our modern history," Waltz said.

"Rather than heeding the advice of military leaders and lawmakers, Biden created a humanitarian crisis in Afghanistan that he alone owns all for the sake of seeking a headline that he would withdraw US troops prior to the 20th anniversary of September 11," he said.

"Now, we will have shamefully given away the freedoms of Afghans, our military equipment and infrastructure, and countless other resources to the hands of Taliban terrorists because of the President's cluelessness and stubbornness," Waltz alleged.

"Additionally, it is growing more likely by the day we will have broken our promise to thousands of Afghan allies who stood should-to-shoulder with our troops on the battlefield that have now been handed a death sentence for our failure to safely evacuate them in a timely fashion," he said.

"The intelligence community has made it clear that Al Qaeda 3.0 will come roaring back as the Taliban have made no indication they have cut ties with the perpetrators of September 11," Waltz said.