As Washington is gearing up its diplomatic efforts in Southeast Asia, it is equally important to maintain a sound relationship with China for the peace and prosperity of the Asia-Pacific region, a senior United States official said on Wednesday.

The remarks, made by US Assistant Secretary of State for Asia and the Pacific Kurt Campbell, came a week before Secretary of State Hillary Clinton departs for the Association of Southeast Asian Nations regional forum and post-ministerial conference in Phnom Penh, Cambodia.

Because of concerns among ASEAN members that this region may become an arena of "dangerous strategic competition" between the US and China, Campbell said: "One of the most important things for us at the forum is to make it clear, particularly to colleagues in ASEAN, that we are committed to a strong, stable and durable relationship with China. It is our strong determination to make it clear that we want to work with China."

Campbell made the remarks during a keynote speech at the second annual conference on maritime security in the South China Sea, held by the Center for Strategic and International Studies.

At the coming meeting in Cambodia, Secretary Clinton and her Chinese counterpart Yang Jiechi will roll out some specific initiatives on capacity building, humanitarian disaster relief, wildlife protection and other issues of common concern, he said.

Clinton's trip is one of the recent intensive diplomatic engagements by the Obama administration in the region, following Defense Secretary Leon Panetta's historic visit to Vietnam and the Joint Chief of Staff Army General Martin Dempsey's visit to the Philippines earlier this month.

Those high-level visits and Americans' frequent presence at the Asian regional meetings show Washington's long-term commitment to regular strategic engagement in the economic dynamic area, the official said.

The Americans are also trying to get their European allies involved more in Asian affairs following their close partnership in Balkan, Afghanistan and Pakistan issues.

European Union foreign affairs chief Catherine Ashton will be invited to the regional forum for the first time as American diplomats are now lobbying their European colleagues into more dialogue and discussions on Asia.

"Campbell described as "dramatically lacking" the level of discussion or strategic engagement between Europe and US over Asia.

Apart the traditional security and defense aspects, Secretary Clinton will lay out a multi-facet diplomatic approach at the regional forum, especially "specific economic initiatives" directed at Southeast Asia, he added.

After the forum, Clinton will take the largest ever business group to North Cambodia's Siem Reap to meet business leadership from ASEAN and other parts of Asia to expand American economic and commercial engagement.

Beijing and Washington have been facing challenges on regional issues in recent years because of China's growing political and economic influence in Asia and the US' reengagement diplomatic policy in the area.

In July, 2010, Secretary Clinton waded into South China Sea territorial disputes by telling a regional security forum in Vietnam that a peaceful resolution of the disputes over the Nansha and the Xisha islands was in the national interests of the US. She also suggested a multilateral solution to the disputes.

China, which has South China Sea territorial disputes with Vietnam, Malaysia, Brunei, and the Philippines, has always tried to resolve the issues through bilateral negotiation.

Beijing accused Washington of interfering in Asian regional affairs and trying to internationalize South China Sea issues.

On recent developments of the issues between China and the Philippines and Vietnam, Campbell said the US has insisted on not taking a position and supported the current diplomatic efforts by the relevant parties.

Bonnie Glaser, an Asia-Pacific security expert at the Center for Strategic and International Studies, said the United States does not view the relations in the region in "zero-sum" terms and is not seeking to force ASEAN members to choose between the world's two largest economies.

She said although the US and some media often pin the blame on China, she believed other claimants over South China Sea territory also sometimes behaved in provocative or confrontational ways that generated concern from the US government.