US National Security advisor Jake Sullivan speaks during the daily press briefing on the situation in Afghanistan at the White House in Washington, DC on August 17, 2021.Andrew Caballero-Reynolds | AFP | Getty ImagesNewly empowered Taliban militants have informed the U.S. that they are prepared to provide safe passage for civilians attempting to flee Afghanistan through an airport in Kabul, the White House said Tuesday.”We intend to hold them to that commitment,” national security advisor Jake Sullivan told reporters amid a barrage of questions about the Biden administration’s handling of the U.S. withdrawal from Afghanistan, which was plunged into chaos as the Islamist insurgents quickly ousted its Western-backed government.Sullivan also said that the “chaotic” situation in the Afghan capital makes it premature to speculate about whether the Taliban could form a government that the U.S. would recognize.CNBC PoliticsRead more of CNBC’s politics coverage:As the Taliban moved into Kabul, thousands of Afghans rushed to the Hamid Karzai International Airport, swarming the tarmac and crowding around planes. Some fell to their deaths as they desperately tried to escape the country by clinging to an aircraft as it took off.Evacuation flights resumed at the airport Tuesday. Sullivan said that the airfield has been secured, and that the White House expects that military cargo planes departing from Kabul will hold about 300 people each on average once the flow of evacuees ramps up.Sullivan also acknowledged receiving reports of people “being turned away or pushed back or even beaten” by the Taliban as they try to cross checkpoints toward the airport. “We are taking that up in a channel with the Taliban to try to resolve those issues. And we are concerned about whether that will continue to unfold in the coming days,” Sullivan said. He added that most people are getting through the gate without issue.The astonishing speed of the Taliban’s takeover, and of the former Afghan government’s collapse, surprised even the Biden administration, which has come under fire from critics across the political spectrum who say the disastrous situation is the result of a rush and bungled withdrawal.A member of Taliban forces (L) sits on a an armoured vehicle outside Hamid Karzai International Airport in Kabul, Afghanistan August 16, 2021.Stringer | ReutersLawmakers of both parties, including Senate Foreign Relations Committee Chairman Bob Menendez, D-N.J., have called for investigation into the administration’s attempt to remove all troops from Afghanistan after nearly two decades of war.Biden “clearly did not accurately assess the implications of a rapid U.S. withdrawal” when implementing the “flawed plan,” Menendez said in a release Tuesday afternoon.The Pentagon’s goal is to get between 5,000 and 9,000 people out of Kabul daily, said U.S. Army Maj. Gen. Henry Taylor, a logistics specialist on the Joint Chiefs of Staff, at a press conference Tuesday.Taylor said that about 4,000 U.S. troops are in stationed in the capital to aid in the evacuation efforts and provide security.The U.S. Embassy in Kabul, which was fully evacuated as the Taliban swept the city, on Monday advised would-be evacuees to fill out a form and shelter in place while awaiting an email with further instructions. Some of Sullivan’s remarks in the contentious briefing echoed President Joe Biden’s rhetoric from a major speech a day earlier, when he defended the decision to pull America out of the country as the better of two bad options.Biden in that address took responsibility for the move, saying “the buck stops with me” — though he also spoke at length about what he described as the lack of willingness by the U.S.-trained Afghan army to fight the Taliban.Asked to clarify if Biden also took responsibility for the gut-wrenching scenes of panic and mayhem at the Kabul airport, Sullivan said the president owns every good decision and “every decision that doesn’t produce perfect outcomes” with respect to the withdrawal.