Image caption Mr Panetta said US naval strength should be enhanced in the Asia-Pacific region

Defense Secretary Leon Panetta has emphasised the importance of a strong US naval presence in Asia, on the eve of a trip to the region.

Speaking at the US naval academy, he said the future of the US depended on ensuring security throughout the Western Pacific and the Indian Ocean.

"America is a maritime nation and we are returning to our maritime roots," he said.

He is due to travel to Vietnam, India and Singapore for a security summit.

Speaking to naval graduates in Annapolis on Tuesday, he said the US should strengthen existing ties with Japan, South Korea, Australia and the Philippines, and form "robust partnerships" with South East Asian nations.

"One of the key projects that your generation will have to face is sustaining and enhancing American strength across the great maritime region of the Asia-Pacific," he told the new naval officers.

The Pentagon chief also spoke about the need to ''strengthen defence ties with China, even as its military is ''growing and modernising''.

''We must be vigilant. We must be strong. We must be prepared to confront any challenge," he said.

But, he added, it was also key to develop a new era of military co-operation with China, in which both countries ''share security burdens in order to advance peace in the Asia-Pacific and around the world''.

Mr Panetta says he will visit China later this year - his first trip as defence secretary.

His speech underscores the new strategic focus of the US on the Asia-Pacific region, amid concerns over how the rise of China and its growing assertiveness over maritime territorial claims might affect the region.

During a visit to Australia in November last year, President Barack Obama said that the region was now a "top priority" of US security policy.

''The United States is a Pacific power, and we are here to stay,'' he said.