VISITING United States Vice- President Joe Biden sought to ease tensions with China by not confronting his hosts in public over the new air defence zone, but highlighting instead both countries' effort to build "a new model" of collaboration.
But experts said Mr Biden was likely to have pressed China's leaders not to implement its contentious Air Defence Identification Zone (ADIZ) during their closed- door meetings, which went on well beyond schedule.
In Mr Biden's meetings with President Xi Jinping and Vice- President Li Yuanchao, both sides discussed ways to advance bilateral ties under the "new model of major-country relations" espoused by Mr Xi and embraced by US President Barack Obama during their summit in California in June.
The closest reference to China's ADIZ was when Mr Xi cited how "regional hot-spot issues keep cropping up", as a reason why strengthening cooperation and dialogue "is the only right choice facing both our countries".
The unexpected silence came a day after Mr Biden and Japanese Prime Minister Shinzo Abe, at their joint press conference in Tokyo, strongly criticised China for unilaterally changing the status quo in the East China Sea by launching the ADIZ on Nov 23.
China wants aircraft, before they fly through its first-ever ADIZ, to comply with self-identification rules or face "defensive emergency response".
The move sparked criticisms from the US, Japan and South Korea, which sent their military planes into the ADIZ without prior identification.
Yesterday, the Chinese Foreign Ministry reiterated Beijing's willingness to hold talks with Tokyo on preventing clashes in their overlapping airspace over the East China Sea, including disputed islands known as Diaoyu to China and Senkaku to Japan.
Speaking in Tokyo on Tuesday, Mr Biden urged China and Japan to set up "crisis management mechanisms and effective channels of communication", even as he pledged to raise concerns "with great specificity" during his two-day visit to Beijing.
More specifically, senior US officials told reporters that Mr Biden would be telling China not to implement contentious procedures related to its ADIZ and also not to set up new zones, such as over the South China Sea.
Analysts say it is likely Mr Biden raised the ADIZ with Mr Xi in private, given that their talks lasted two hours instead of 45 minutes as planned.
"The US knows it is in its interests to assure Japan, while not provoking China as it is impolite for a guest to be publicly telling a host what it should or should not do," said Peking University's Northeast Asia expert Wang Dong.
"It shows the US is not losing its strategic vision nor is it prepared to sacrifice the bigger prize, which is economic cooperation with China."
Mr Biden will meet Premier Li Keqiang today before leaving for South Korea.