Aug 31 (Reuters) - Taliban supporters paraded coffins draped with American and NATO flags in the eastern city of Khost on Tuesday, part of celebrations across the country following the withdrawal of the last U.S. troops. The mock funeral, in which coffins covered in French and British flags were also carried along the street through a large crowd, marked the end of a 20-year war and a hasty and humiliating exit for Washington and its NATO allies. Some of the crowd held guns aloft, while others waved Taliban flags or snapped the procession on mobile phones. "August 31 is our formal Freedom Day. On this day, American occupying forces and NATO forces fled the country," Taliban official Qari Saeed Khosti told local television station Zhman TV during its coverage of the event. Footage from Khost was shared widely on social media on Tuesday alongside other videos of celebratorygunfire in the capital Kabul and a man dangling from a U.S.-made Black Hawk helicopter circling above Afghanistan"s second-city Khandahar. Reuters could not verify all the videos. The last U.S. soldier boarded the final flight out of Afghanistan a minute before midnight on Monday, ending a chaotic evacuation of 123,000 civilians from Afghanistan. In a lightning sweep back to power, the Taliban ousted a government backed and equipped by the United States and captured U.S.-made weapons and hardware left behind by fleeing Afghan forces. Other images shared online on Tuesday showed Taliban members walking through Kabul airport in U.S.-supplied fatigues, some brandishing gleaming rifles and others trying out state-of-the-art night vision goggles or sizing up U.S. helicopters. Pentagon spokesman John Kirby said the U.S. military was not concerned by the images as the helicopters could not be flown. The departing U.S. troops destroyed more than 70 aircraft and dozens of armoured vehicles. They also disabled air defences that had thwarted an attempted Islamic State rocket attack on the eve of their departure.