Biden's focus

In Washington on Wednesday, a senior US official said in a briefing on Vice-President Joseph Biden's Asia trip that he will convey US concerns directly to Chinese leaders and seek clarity regarding China's intentions.

Biden leaves on Sunday, heading to Japan, China and South Korea.

Xing said: "There is no reason for the US to blame China for establishing such a zone, because Washington was the first ... to set up such a zone. It also strengthened its air defense zone system after the Sept 11 terrorist attacks.

"It is Japan's illegal 'purchase' of China's Diaoyu Islands that fueled tensions in East Asia."

The US official, who did not give his name, said of Biden's visit: "He's going to have a very high-level and a very wide-ranging dialogue with the senior Chinese leadership that covers a wide range of shared interests along with areas of concern.

"He will pick up where President (Barack) Obama and President Xi (Jinping) left off after Sunnylands and the G20, with the kind of high-level personal engagement between the top leadership of our two countries that is an essential part of advancing the US-China relationship in the 21st century," the official said.

He was referring to the informal summit between Xi and Obama at the Sunnylands private estate in California in early June.