▶ Watch Video: CBSN Washington — President Biden will provide an update Tuesday about his administration’s efforts to evacuate thousands of U.S. citizens and vulnerable Afghans from Kabul as he faces questions about whether the August 31 deadline to pull the remaining American forces from the country will stand. Mr. Biden said Sunday discussions were taking place with military officials as to whether he would push back his deadline for withdrawing the final U.S. troops from Afghanistan to ensure all Americans and at-risk allies are safely shuttled out of the country. Roughly 6,000 service members were sent to Afghanistan to assist with the evacuation efforts after the collapse of the Afghan government and rapid Taliban takeover sparked chaos in the capital of Kabul. How to watch President Biden’s remarks on Afghanistan What: President Biden delivers remarks on the evacuation efforts in Afghanistan When: Tuesday, August 24 Time: 12 p.m. ET Location: The White House Online stream: Live on CBSN in the player above or on your mobile or streaming device While the president has said he hopes American forces will not have to stay in Kabul past August 31, House Intelligence Committee Chairman Adam Schiff, a Democrat from California, told reporters Monday after a briefing on Afghanistan it is “very unlikely” the evacuation can be completed in the next week given the number of Americans and Afghans who still need to leave. A Taliban spokesman, however, warned there would be “consequences” if the U.S. or United Kingdom were to keep forces in Afghanistan after the end of the month. Jake Sullivan, Mr. Biden’s national security adviser, said Monday the U.S. is “engaging” and “consulting” with the Taliban on the situation in Afghanistan. A source familiar with the situation confirmed to CBS News that CIA Director William Burns met with the Taliban’s de facto leader, Abdul Ghani Baradar, on Monday in Kabul. The Washington Post first reported the meeting. Over the last few days, the U.S. has ramped up the pace of evacuations from the airport in Kabul, with roughly 21,600 people evacuated over a 24-hour period beginning early Monday morning, according to a White House official. Thirty-seven U.S. military aircraft carried about 12,700 evacuees, while 57 coalition flights brought 8,900 people out of the country. Since August 14, roughly 58,700 people have been relocated, though it’s unclear how many are U.S. citizens. Sullivan said the U.S. has contacted Americans who are still in Afghanistan by phone, email and text to give specific instructions on departing the country and said the government has “developed a method to safely and efficiently transfer” U.S. citizens to the airfield in Kabul. Olivia Gazis contributed to this report.