U.S. Vice President Joe Biden said Thursday that Washington and Beijing have forged "real cooperation"

in reining in North Korea's nuclear and missile programs, while expressing concerns that Beijing's new air defense zone has caused "significant apprehension" in the region.

Speaking at a meeting with business leaders in Beijing, Biden also reaffirmed that the U.S. will remain a diplomatic, economic and military power in the Asia-Pacific region because Washington "has a profound stake on what happens here."

Biden, who held talks with Chinese President Xi Jinping on Wednesday, said that stopping "the spread of weapons of mass destruction, including North Korea's destabilizing nuclear and missile programs, are where we have real cooperation.

During the talks with Xi, Biden said that the U.S. doesn't recognize the Chinese air defense zone that partly overlaps those of South Korea and Japan, and "President Xi was equally clear in laying out their view of the zone and of territorial disputes in the region," according to a pool report citing senior U.S. officials traveling with Biden.

"China's recent and sudden announcement of the establishment of a new Air Defense Identification Zone has, to obviously state, caused significant apprehension in the region," Biden told the Thursday meeting with business leaders.

"I was very direct about our firm position and our expectations in my conversations with President Xi," Biden said.

Biden admitted that the U.S. and China have a "complex" relationship, saying, "We have our differences and they are real.

"But there is nothing inevitable about a conflict with China," he added. "Wholesome competition and strong competition is fundamentally different than conflict."

Regional tensions have risen sharply following China's Nov. 23 declaration of its Air Defense Identification Zone (ADIZ) that overlaps those of South Korea and Japan. It requires all aircraft entering the zone to notify Chinese authorities and follow their instructions, or face "defensive emergency measures."

South Korea, Japan and the United States have defied the new Chinese air defense zone, which is mainly viewed as an attempt to bolster Beijing's claim over a set of islands at the center of a bitter territorial dispute with Japan. The islands are called Senkaku in Japan and Diaoyu in China.

Biden arrived in Beijing from Tokyo on Wednesday on the second-leg of his Asian tour. He will head for Seoul later Thursday for talks with South Korean President Park Geun-hye.

In Seoul, North Korea's nuclear standoff and the Chinese air defense zone are expected to top the agenda of the talks between Park and Biden.

Since conducting its third nuclear test earlier this year, North Korea has repeatedly expressed its willingness to reopen the six-party process "without preconditions."

South Korea and the U.S. have been demanding North Korea show its sincerity first by taking steps to denuclearize itself. China has been more accommodating toward North Korea, urging South Korea and the U.S. to lower their bar for Pyongyang to sit down at the negotiating table.

The six-party talks, which involved the two Koreas, the U.S., China, Russia and Japan, have been dormant since late 2008. (Yonhap News)