U.S. Vice President Joe Biden and Chinese President Xi Jinping met Wednesday in Beijing, but neither publicly commented on China's new air defense zone, or ADIZ, that has raised regional tensions.
After their initial meeting inside Beijing's Great Hall of the People, Biden said relations between the two sides must be based on trust. But he made no mention of the ADIZ, which was a major focus of his talks in Japan on Tuesday.
Xi also made no direct mention of the controversy, saying only that relations between Washington and Beijing have generally maintained "positive development" but that "regional hotspot issues" keep cropping up.
Even though neither man made a direct reference to China's ADIZ in front of reporters, Biden had promised to raise the issue during his talks with Chinese leaders.
The visit to Beijing comes one day after a visit to U.S. ally Japan, where Biden said he was "deeply concerned" by China's Air Defense Identification Zone in the East China Sea.
Air defense zones claimed by China and Japan
After meeting Japanese Prime Minister Shinzo Abe, Biden suggested establishing "confidence-building measures, including emergency communications channels" to help reduce tensions.
Joseph Cheng, a political science professor at the City University of Hong Kong, tells VOA that such measures could be welcomed by both sides.
"Some kind of hotline is definitely possible. I think all parties concerned welcome this. And further discussions on confidence building measures are to be welcomed. Ideally, there should be some sort of code of conduct along the lines of that concluded between China and ASEAN," says Cheng.
But Cheng does not expect Biden to take on a formal mediating role, since China has been reluctant to involve outside powers in what it views as bilateral territorial disputes.
Further dialogue could also be complicated by Japan's refusal to formally recognize a dispute over the islands, something it sees as a weakening of its position.
Bonnie Glaser, a China expert at the Washington-based Center for Strategic and International Studies, tells VOA that Biden finds himself in a tough position.
"It is quite difficult for Vice President Biden in this particular heightened, tense atmosphere, to try and urge the two sides to resume political dialogue and particularly to talk about confidence building measures between the two militaries," says Glaser.
China late last month set up its Air Defense Identification Zone. Beijing has requested that all airplanes submit flight plans ahead of flying through the zone.
The U.S. has repeatedly rejected the Chinese zone. Last week, it flew two unarmed B-52 bombers on "routine" training missions through the area, ignoring Chinese demands the aircraft identify themselves.
While Beijing said it monitored the B-52 flights, it did not interfere. Later, however, it did scramble fighter jets to the area, heightening concerns about a possible miscalculation in the air.
Ahead of Biden's arrival, China's Defense Ministry said its determination to defend the zone are "unwavering, and the military is fully capable of exercising effective control" over the area.
The state-controlled China Daily
newspaper also warned in an editorial Wednesday that Biden "should not expect any substantial headway if he comes [to China] simply to repeat his government's previous erroneous and one-sided remarks."
After visiting China on Wednesday, Biden will head to South Korea Thursday, which has also been angered by China's declared air defense zone.
He is expected to meet with President Park Geun-hye and visit the demilitarized zone with the North before returning to Washington.