Lobbying world leaders, President Bush sought China's support Sunday for pressuring long-defiant North Korea to prove it is serious about dismantling its nuclear weapons program. Bush used a summit of Pacific Rim countries to consult individually with leaders of the four other nations engaged with North Korea in nuclear disarmament talks, stalled for more than a year but now on the verge of resumption. Those talks were expected to win endorsement from all 21 participants in the annual meeting of the Asia-Pacific Economic Cooperation forum. The US president met Sunday with Chinese President Hu Jintao and was to talk later with Russian President Vladimir Putin. In this communist country, Bush made a pointed effort to encourage religious tolerance. He and his wife, Laura, attended services at Cua Bac Church, a concrete basilica built by the French more than a century ago. Just ahead of Bush's trip, The United States dropped Vietnam from a list of countries said to severely violate their people's religious freedoms.