UPDATE 1-Trump asked S.Korea officials to show flexibility in trade talks -Seoul

-Seoul@ (Adds statement from USTR spokeswoman in Washington)

SEOUL, March 16 (Reuters) - U.S. President Donald Trump asked South Korean officials to show flexibility in trade negotiations with the United States in a phone call with South Korean President Moon Jae-in, the Blue House said in a statement on Friday.

South Korea and the United States were scheduled to hold a third round of talks for amendments to an existing bilateral free trade agreement known as KORUS this week in Washington.

"Officials from the United States and the Republic of Korea held discussions and are expeditiously negotiating amendments and modifications to the KORUS agreement," Emily Davis, a spokeswoman for the office of the U.S. Trade Representative, said late on Friday.

"The United States emphasized rebalancing the agreement and addressing implementation issues, Davis said in a statement.

Trump has repeatedly said the free-trade deal with South Korea is "unfair" and has threatened to scrap it altogether on multiple occasions. (Reporting by Christine Kim and Eric Walsh in Washington; Editing by Janet Lawrence and Lisa Shumaker)