WASHINGTON (Reuters) - President Joe Biden on Friday said the U.S. commitment to the NATO alliance was “unshakeable” and promised to observe the principle that an attack on one member was an attack on all. His statement was at odds with his predecessor, Donald Trump, who called the 30-member alliance outdated and at one point suggested Washington could withdraw. “The United States is fully committed to our NATO alliance, and I welcome your growing investment in the military capabilities that enable our shared defenses,” Biden told an online session of the Munich Security Conference. “An attack on one is an attack on all. That is our unshakeable vow.” Trump administration officials had publicly hammered, and sought to shame, Germany and other NATO members for not meeting a target of spending 2% of their gross domestic output on defense. Biden’s comments signaled a different approach - and one sure to be welcomed by European leaders and NATO officials. “America’s back,” Biden told the security conference after his first virtual meeting with Group of Seven world leaders. “I know the past few years have strained and tested our transatlantic relationship, but the United States is determined - determined - to re-engage with Europe, to consult with you, to earn back our position of trusted leadership,” he said.Biden said the U.S. military was conducting a comprehensive review of its military posture around the world, but he had lifted orders to withdraw U.S. troops from Germany - another decision by the Trump administration that had shocked allies. In addition, Biden said he had lifted a cap imposed by the previous administration on the number of U.S. forces that could be based in Germany.