Biden’s comments to ABC News were his most extensive to date about the deadline set in an accord struck with the Taliban under former President Donald Trump in February 2020. His interview aired a day before Russia, China, the United States, Pakistan, a delegation of top Afghan officials and opposition leaders and Taliban negotiators meet in Moscow in an attempt to kickstart deadlocked peace talks. Some U.S. officials and many experts fear that if U.S.-led international forces depart before a peace deal is reached, Afghanistan could plunge into a new civil war, giving al Qaeda a new sanctuary. “I am in the process of making that decision now as to when they will leave,” Biden said of the last 2,500 U.S. troops in Afghanistan. “It could happen, but it is tough.” Biden said Trump’s agreement was not “very solidly negotiated.” Even so, Biden has retained as his own peace envoy Zalmay Khalilzad, the veteran U.S. diplomat who worked the deal out for Trump. The Taliban has warned it could resume attacks on U.S.-led international forces if Biden misses the deadline. The 2020 accord specified a phased conditions-based U.S. withdrawal. Trump ordered it to proceed despite a surge in violence blamed mostly on the Taliban, a six-month delay in intra-Afghan peace talks and what U.S. officials say is the Taliban’s failure to fulfill a commitment to cut ties with al Qaeda. This diluted U.S. negotiating leverage. The Taliban has denied that al Qaeda fighters remain in Afghanistan, where the insurgents provided the Islamist extremists with sanctuary as they planned the Sept. 11, 2001, attacks on the United States. The Taliban deny responsibility for the escalating violence. On taking office, Biden ordered a review of the 2020 deal. But in retaining Khalilzad, Biden adopted in large part a proposed peace accord drafted at the end of Trump administration calling for U.S.-backed Afghan President Ashraf Ghani to surrender power to an interim administration, half of whose members the Taliban would select. Ghani has repeatedly rejected standing aside, saying elections should decide a change in government. The Taliban reject democratic elections and the nationwide ceasefire called for by the U.S. proposal.