WASHINGTON, March 8 (Reuters) - U.S. President Donald Trump and North Korean leader Kim Jong Un will meet by May and Kim has pledged to refrain from further nuclear or missile tests, South Korea's national security chief said on Thursday after briefing White House officials on talks between Seoul and Pyongyang.

"Kim pledged that North Korea will refrain from any further nuclear or missile test," South Korea's National Security Office head Chung Eui-yong told reporters at the White House.

"President Trump ... said he would meet Kim Jong Un by May," Chung said. (Reporting by Steve Holland; Writing by Mohammad Zargham; Editing by Eric Beech)