The top US commander in the Pacific expressed concern Thursday that he has no direct line to his counterpart in China in the case of a crisis in the region.

Amid tensions between China and Japan in the East China Sea, Admiral Samuel Locklear said he wanted a hotline to officers from the People's Liberation Army to defuse potential conflict.

"I don't have the ability to pick up a phone and talk directly to a PLA navy admiral or general at the time of a crisis. And we need to work on that," Locklear told a news conference.

The issue has been discussed between the two governments, he said, "but things take time."

The head of US Pacific Command said Pentagon chief Chuck Hagel and the chairman of the US Joint Chiefs of Staff, General Martin Dempsey, occasionally consult their counterparts by phone.

"Would that work in the time of a crisis? We hope it would work," the Locklear said.

The United States and China agreed to set up a direct telephone link between the two countries' defense ministries in 2008 -- but it has yet to be tested in an emergency.

Analysts say top officers do not have a channel to confer with their counterparts in an urgent situation, unlike in the days of the famed "red phone" with Moscow during the Cold War.

In December, a US guided missile warship, the Cowpens, had to make a sharp turn to avoid colliding with a Chinese naval ship that cut in front of it, according to the Pentagon.

US naval officers said the incident showed why Chinese and American military leaders need a working hotline.

Locklear, who oversees US forces across the Asia-Pacific, said regular communication with China was vital and warned misunderstandings could trigger a conflict in the East China Sea, where Japan and China are locked in a bitter territorial dispute.

Asked about the dispute, Locklear said: "I am concerned, any time you have two large powers, two large economic powers, two large military powers, that have a disagreement that they're not talking to each other about, that has no clear diplomatic end state in sight, that the risk of miscalculation can grow."

He said stand-offs over contested islands in the area often involve "young naval officers, young civilian mariners" from China or Japan who are inexperienced.

The admiral urged both sides to reach a diplomatic solution over the islands, which Japan calls Senkaku and China refers to as the Diaoyus.

"We have to continue to encourage restraint, we have to continue to encourage professionalism, we have to continue to hope that there will be diplomatic dialogue," he said.

The dispute is "not productive for the region and it needs to be ultimately resolved," he added.

The feud over the islands has come perilously close to erupting into armed clashes in recent years.

Japan has called on China to help arrange a communication channel between the two countries' armed forces.