U.S. to bolster air, navy activity in northern Australia - source

Australian Governor-General Sir Peter Cosgrove (R) greets U.S. Secretary of State John Kerry, next to (L-R) U.S. Secretary of Defense Chuck Hagel, Australian Defence Minister David Johnston and Australian Foreign Minister Julie Bishop before the AUSMIN meeting at Admiralty House in Sydney, August 12, 2014. REUTERS/Jason Reed

SYDNEY (Reuters) - The United States will bolster its air and navy presence in northern Australia, a source said on Tuesday, under a plan to strengthen defence ties with its regional ally and project more power into the Asia-Pacific, where China's influence is growing.

U.S. Defense Secretary Chuck Hagel and Secretary of State John Kerry are in Sydney to finalise an agreement reached between U.S. President Barack Obama and Australian Prime Minister Tony Abbott on the deployment of U.S. marines to Australia for joint exercises and training.