The Cipher Brief Open Source Report for Tuesday, September 7, 2021

Secretary of State Antony Blinken says Taliban are cooperating to let Americans with valid travel docs leave Afghanistan, while some experts call into question that claim; The US reports four Americans were evacuated via an overland route out of Afghanistan; Former UK Prime Minister Tony Blair says the west should prepare for a bio-terror attack while Iran's new president says he is ready for nuclear talks, with conditions.