WASHINGTON (AP) ― A high-level U.S. delegation will urge key allies Japan and South Korea to mend strained ties that have hurt security cooperation. It will also likely remind the new government in Tokyo that any disavowal of its apology for the use of sex slaves in World War II would make matters worse.

Senior officials from the State Department, Pentagon and White House will travel to Seoul and Tokyo next week after recent elections in both countries. The two Northeast Asian democracies have fallen out over a territorial dispute and Japan’s attitude toward its colonial past.

The trip also takes place against a backdrop of more threatening tensions between Japan and China over disputed islands in the East China Sea. Media reports suggest Japan’s new government may take a tougher line on what it considers repeated Chinese incursions into its territorial waters.

The top U.S. diplomat for East Asia, Kurt Campbell, said Thursday the U.S. will urge “care and caution” in that maritime dispute. The tiny islands are called Senkaku in Japanese and Diaoyu in Chinese, are controlled by Japan but also claimed by China and Taiwan.

Tensions intensified after Tokyo bought the islands from their Japanese private owners in September. The U.S., which could be compelled under treaty obligations to assist Japan in event of a conflict, has since called for “cooler heads” to prevail, but the dispute rumbles on.

A trough in relations between Japan and South Korea has further clouded the outlook in the region, at a time when the Obama administration is looking to foster security cooperation between its allies. That’s a key plank of America’s “pivot” toward the Asia-Pacific as it shifts diplomatic and military attention from Iraq and Afghanistan.

In June, a planned intelligence-sharing pact between Japan and South Korea was derailed. Then in August, a visit by South Korea’s outgoing President Lee Myung-bak to small islands claimed by both nations led to angry exchanges between them.

“After a period of very substantial warming between Japan and South Korea, there have been tensions over the course of the last year or so that undermined the quality of the relationship,” Campbell said at the Carnegie Endowment for International Peace, a Washington think tank. He said a key reason for the U.S. delegation’s visit was to ensure both governments are committed to “rebuilding” their ties.

Japan’s new nationalist Prime Minister Shinzo Abe sent a representative last week to meet with South Korea’s president-elect Park Geun-hye, offering some hope for rapprochement. But suggestions that Abe may disavow a 1993 statement in which Japan apologized for the suffering of so-called “comfort women” during World War II risks riling South Korea.

The U.S. will be quietly urging Abe’s government against such a step, said Victor Cha, a former White House director of East Asia policy. But he added that the U.S. will not want to be seen as publicly mediating in a touchy historical dispute.

“You will never succeed and both sides will end up hating you for it,” Cha said.

Historians say up to 200,000 women, mainly from the Korean peninsula and China, were forced to provide sex for Japanese soldiers in military brothels. But rightists in Japan question whether the women were coerced by the military to be prostitutes.

Campbell will be accompanied by Assistant Secretary of Defense Mark Lippert and National Security Council Senior Director for Asian Affairs Daniel Russel. They arrive in Seoul on Tuesday and travel to Tokyo Wednesday ― a prelude to a trip to Washington by Japan’s new Foreign Minister Fumio Kishida that Friday.

Cha said he also expected the U.S. delegation to sound out Park’s transition team in South Korea on how she will approach relations with North Korea, including on how to respond should Pyongyang follow up last month’s long-range rocket launch with a nuclear test.