President Joe Biden defended his decision to withdraw all U.S. military forces from Afghanistan on Monday amid the collapse of the country’s government.

“Our mission in Afghanistan was never supposed to have been nation-building,” Biden, speaking from the East Room of the White House, said in a televised national address. “It was never supposed to be creating a unified, centralized democracy. Our only vital national interest in Afghanistan remains today what it has always been: preventing a terrorist attack on American homeland.”