U.S. Secretary of State Hillary Clinton visits seven countries on a two-week Asian tour beginning Wednesday, but one of them - China - looms larger than all the rest.

The centerpiece of the tour is this week's meetings in Vietnam of the Association of Southeast Asian Nations and the larger East Asia Summit.  Earlier ASEAN meetings this year have been preoccupied with territorial disputes between China and its neighbors over islands in the South China Sea.

And a territorial dispute in the East China Sea between China and Japan is expected to come up at Clinton's first stop - in Hawaii for a meeting with Japanese Foreign Minister Seiji Maehara.

A last-minute change in Clinton's itinerary takes her to China's Hainan Island for talks with a senior official ahead of a state visit to Washington in January by Chinese President Hu Jintao.

Even at Clinton's other stops - in Cambodia, Malaysia, Papua New Guinea, New Zealand and Australia - China's rising power is expected to be discussed.

U.S. officials say they consider it vital to have a "strong constructive relationship" with China. But at the same time, they want to reassure other countries that the United States will not reduce its role in the region as China expands its own.

Some information for this report was provided by AP and AFP.