PRAGUE, April 5 (Xinhua) -- The United States is ready to take the lead in the global efforts to tackle climate change, U.S. President Barack Obama said on Sunday, signaling a policy change of Washington.

    "To protect our planet, now is the time to change the way that we use energy," he said while addressing a crowd at a square outside the Prague Castle.

    It was Obama's first public speech abroad since he took office in January. He is in the Czech Republic for a summit with European Union (EU) leaders on the last leg of his first European trip as the U.S. president.

    "Together, we must confront climate change by ending the world's dependency on fossil fuels by tapping the power from the sources of energy like the wind and the sun and calling upon all nations to do their part," Obama said.

    "And I pledge to you that in this global effort, the U.S. is now ready to lead," he added.

    The EU has accused Washington of being reluctant to make commitments of cutting greenhouse gas emissions. It is one of the major polluters that have not ratified the Kyoto Protocol, a key international legal instrument setting specific goals for countries to reduce their greenhouse gas emissions by 2012.

    With the Kyoto Protocol nearing expiry, the EU is pushing hard for a new deal and an international conference is due to be held by the end of this year.

    The EU had hoped the Obama administration would bring change to the U.S. policy on climate change.