The United States was not forewarned of South Korea's recent decision to terminate a military intelligence-sharing pact with Japan that helps the U.S. allies counter missile threats from North Korea, a senior U.S. defense official said Wednesday.

Noting that there have been "consultations" over the issue, Randall Schriver, assistant secretary of defense for Indo-Pacific security affairs, said at a Washington think tank, "In terms of the actual decision to not renew (the pact), we were not forewarned."

Later in the day, U.S. Defense Secretary Mark Esper urged Japan and South Korea to end their escalating feud, in the latest indication that the Trump administration was concerned that the spat was damaging America's regional alliance network.