The Biden administration doubled down Thursday on its unusual court battle to derail a plea deal that the government itself had reached with accused 9/11 mastermind Khalid Sheikh Mohammed. It urged a federal appeals panel to block Mohammed's guilty plea from going forward as scheduled Friday at Guantanamo Bay, Cuba. Defence lawyers described the attempts to throw out the agreement as the latest in two decades of fitful and negligent mishandling of the case by the US military and successive administrations. The fight has put the Biden administration at odds with the US military officials it had appointed to oversee justice in al-Qaida's attacks on Sept 11, 2001, that killed nearly 3,000 people. It was the latest tumult and uncertainty in two decades of troubled prosecution tied to one of the deadliest attacks on American soil. A new filing Thursday from Justice Department lawyers argued that the gravity of the extraordinarily important case warranted Defence Secretary Lloyd Austin ..