Japan and South Korea need time to cool down from a feud hurting security ties, former Defense Minister Itsunori Onodera said of the dispute that the Trump administration warns could damage its regional alliance network.

Onodera, who has served two stints as defense minister under Prime Minister Shinzo Abe, said "time will resolve it," indicating to leaders who have shown no signs of backing down that returning to an even keel was in everyone's interests.

Relations between Tokyo and Seoul have plumbed new depths over the past few months, as lingering resentment over Japan's 1910-1945 colonial rule of the Korean Peninsula resurfaced. Disputes have damaged trade and tourism, as well as military ties between the two U.S. allies.