U.S. Secretary of State Hillary Clinton is traveling to the South Pacific for the start of an Asia-Pacific tour designed to reassert American interests in a region where China's influence is growing.

Clinton departed Washington Thursday for the Cook Islands, where she will become the first top U.S. diplomat to attend the annual Pacific Islands Forum of regional officials. The forum is one of the biggest events ever to be held in the island chain of only about 10,000 people.

Climate change is one of the most pressing issues for the tiny islands of the South Pacific. Many are threatened by rising waters blamed on global warming. Pacific island nations have historic ties with the United States dating back to the Second World War, but in recent years they also have been seeking Chinese investment.

U.S. State Department officials say the agenda for Secretary Clinton's regional tour also includes territorial disputes between China and its neighbors over the South China Sea.

Washington has been critical of China's increasingly aggressive maritime claims in the region, which is thought to contain vast amounts of oil and gas reserves.

A Thursday commentary in China's state-run Xinhua news agency questioned Clinton's trip, saying it is “aimed at curbing China's growing influence” in the South Pacific.

The strongly worded editorial said the U.S. is intentionally “stirring up disputes” in the region, and called on Washington to “abandon its surreal ambition of ruling the Asia-Pacific and the world.”

Observers say Clinton's visit – her third to Asia since May – underscores the importance of the Obama administration's recent “pivot” toward Asia.

But Ralph Cossa, a security analyst at the Pacific Forum in Hawaii, says the increased U.S. attention does not mean Washington is trying to contain the rise of China.

“China wouldn't be rising if it weren't for U.S. investment and U.S. policy since the Nixon administration's policy of engaging China and helping it to grow,” says Cossa. “So if we're trying to contain China, we're sure going about it the wrong way by putting billions of dollars in investment to make China part of the industrialized world.”

Regarding the South China Sea disputes, Cossa says he expects little progress when Clinton is expected to raise the issue during meetings with Chinese leaders in Beijing next week.

“It's a real dialogue of the deaf, in some respects. The Chinese think we're meddling, and we think we're acting as a responsible major power that is concerned about our allies, concerned about freedom of navigation, and concerned about regional stability.”

Clinton's trip will also take her to Brunei, Indonesia, East Timor, and Russia, where she will lead the U.S. delegation at the Asia Pacific Economic Forum on September 8-9.