In an apparent bid to allay fears of an American pullback from Northeast Asia, President-elect Donald Trump's pick for national security adviser has called U.S.-South Korean ties a "vital alliance" as the two nations seek to rein in North Korea's nuclear weapons program, a South Korean official said Saturday.

Trump adviser and retired U.S. Army Lt. Gen. Michael Flynn made the comments during talks Friday with a delegation of South Korean officials visiting the U.S. to gauge the incoming administration's position on the alliance, South Korea's presidential deputy national security adviser Cho Tae-yong was quoted as saying by the Yonhap news agency.

"He characterized the Korea-U.S. alliance as a vital alliance, and the basis of the alliance should continue to be strengthened," Cho said of the one-hour meeting with Flynn.