U.S. Vice President Joe Biden is expressing renewed concern over China's newly declared air defense zone, as he begins his Asia trip with talks in Tokyo.
Biden told the Asahi Shimbun newspaper that Washington remains "deeply concerned" at the zone, which includes islands also claimed by U.S. ally Japan.
The U.S. leader said the move underscores the need for China and Japan to "establish crisis management and confidence building measures to lower tensions."
Biden met early Tuesday with Japan's deputy prime minister, Taro Aso. Later, he meets Prime Minister Shinzo Abe, before heading to Beijing on Wednesday.
Tomohiko Taniguchi, an Abe aide, tells VOA Washington and Tokyo agree on how to handle the situation with Beijing, which he called serious.
"This is no longer an issue between Japan and China because the zone covers the vast majority of the East China Sea. It's the most serious challenge to internationally accepted norms for freedom of movement in the sky and freedom of navigation in the sea."
Some in Japan want the U.S. to take a stronger position on the island dispute. The U.S. does not take an official position, but officials say the islands do fall under a treaty obligating Washington to defend Japan if attacked.
Japanese Chief Cabinet Secretary Yoshihide Suga said Tuesday that he is confident that Biden will deliver a strong message when he visits Beijing.
"We have tightened the U.S.-Japan alliance since China set the air identification zone and I think (Biden) will tell China that China's actions will unilaterally change the region's status and that this action is dangerous and that it will not be accepted."
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 they identify themselves.
But Washington officials have recommended U.S. commercial airlines comply with China for the safety and security of passengers. Some view this as a concession of Chinese sovereignty.
White House spokesman Jay Carney on Monday insisted this is not the case, saying the U.S. continues to "not accept the legitimacy of China's requirements."
A White House statement also said that Biden will raise the air defense zone issue when he meets this week with Chinese President Xi Jinping and other officials.
On Tuesday, the Communist Party-controlled Global Times said in an editorial if Biden "wants a successful trip" to China, he will be careful not to express open support for Tokyo's claims.
Biden's stop in Tokyo is the first on a six-day tour of Asia. He 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.