WASHINGTON, July 17 - U.S. Secretary of State Marco Rubio heads this weekend to meetings of Asia-Pacific countries in Manila, where he is expected to meet with his Chinese counterpart to prepare a possible September summit between Chinese leader Xi Jinping and U.S. President Donald Trump.

Russian Foreign Minister Sergei Lavrov is also expected to be in Manila next week for meetings involving the 11-member Association of Southeast Asian Nations (ASEAN) along with the Chinese foreign minister, Wang Yi, and ministers from Japan, Australia, Canada and Britain.

The gatherings come at a time of global instability, with the Iran war disrupting global trade and creating economic stress across Asia.

The U.S. State Department said Rubio would leave for Manila on Sunday to attend the ASEAN Post-Ministerial Conference, the East Asia Summit Foreign Ministers' Meeting, and the ASEAN Regional Forum Foreign Ministers' Meeting.

It said Rubio will also meet with senior government officials from Indo-Pacific countries in a trip lasting until next Thursday.

"The Secretary's visit advances a clear U.S. priority: a free and open Indo-Pacific that delivers safety, security, and prosperity for the region and for the American people," a statement said, adding that Rubio would also use the trip to deepen the U.S. partnership with the Philippines.

The U.S. and China have yet to confirm whether their top diplomats will meet during the forum, although it is widely expected and representatives from the two countries have previously done so.

Analysts say a Rubio meeting with Wang Yi is likely to focus on preparations for a second summit this year between Trump and Xi following their last meeting in May. Trump has said Xi will visit the U.S. at the end of September.

Tense U.S.-China relations have stabilized under a temporary trade truce reached by Trump and Xi in October, but deep differences define ties, which many analysts see mired in a new form of Cold War.

SOUTH CHINA SEA, MYANMAR ON THE AGENDA