By David Brunnstrom, Idrees Ali and Ju-min Park WASHINGTON/SEOUL (Reuters) -When South Korean President Lee Jae Myung meets U.S. President Donald Trump next week for their first summit, he will be asked to pay more for the upkeep of American troops on the peninsula during talks set to be dominated by security issues and China.

Barely two months into office, South Korean President Lee Jae Myung faces a pivotal foreign policy test, heading into back-to-back summits in Tokyo and Washington that reflect the wider struggle of U.

On his first official visit to Japan since taking office in June, Lee will meet Prime Minister Shigeru Ishiba at the premier's residence in Tokyo to discuss bilateral ties, including closer security cooperation with the United States under a trilateral pact signed by their predecessors.