PELELIU ISLAND, Palau » Visiting the remote Western Pacific site of one of the fiercest battles of World War II, Emperor Akihito and Empress Michiko of Japan offered flowers and prayers on Thursday to mark the coming 70th anniversary of the end of a conflict that continues to haunt Japan as it seeks a larger role in the world.

The short trip by the imperial couple to Peleliu, a small island that is now a popular diving spot in the Republic of Palau, is part of Japan’s broader efforts to commemorate the approaching anniversary of its defeat on Aug. 15, 1945. During their three hours here, the emperor and empress braved a harsh tropical sun to pay solemn tribute at the separate memorials erected to the 10,200 Japanese soldiers and 1,600 Americans who died here.

In that battle in 1944, the outnumbered Japanese defenders fought and held out for more than two months in the name of Akihito’s father, Emperor Hirohito. Today, residents still find bones of Japanese soldiers in the caves where they battled to the last man.

"We believe that we must never forget that those beautiful islands in the Pacific Ocean have such a tragic history," Akihito, 81, said Wednesday as he boarded a plane in Tokyo for a two-day visit to Palau.

Yet, it is precisely the perception that Japan is having trouble remembering the darker episodes of the war that is hurting relations with its two closest neighbors, China and South Korea, and raising concerns in the United States, its longtime ally. The source of these doubts has not been the emperor, who has called for remembering the suffering caused by the war, but Japan’s right-leaning prime minister, Shinzo Abe, who has at times appeared less than apologetic for his nation’s wartime militarism.

Though Abe has expressed public remorse for the war, suspicions that he remains an unrepentant revisionist at heart have dogged his efforts to give his long-passive nation a more assertive regional role. The leaders of both China and South Korea, two former victims of Japan’s early 20th-century empire-building, have so far refused to hold full-blown summit meetings with Abe, though observers point out that they may also be pandering to anti-Japanese sentiments at home in order to bolster their own political support.

Still, analysts say Abe and his government have not helped by sending mixed signals about their stance on the war as the anniversary approaches. Though Abe has said he will uphold Japan’s past apologies for its wartime aggression, he has also added the vague qualifier that he wants to uphold them "as a whole," leaving room for suspicion that he may try to water down those parts of previous statements of remorse.

"Abe himself has sown a lot of doubts about Japan’s intentions," said Jennifer Lind, an expert on Asia’s history disputes at Dartmouth College in New Hampshire. "It’s ironic that while he wants to be this forward-looking nationalist who is building up Japan’s power, he keeps putting history on the agenda by denying the past."

These days, clashes over history seem to have become an all too common occurrence between Japan and its close neighbors. Earlier this week, South Korea and China criticized moves by the Japanese Education Ministry to force publishers of middle-school textbooks to recast descriptions of sensitive episodes in history to conform to the official stance of Abe’s government.

In one case, a publisher was forced to revise a section on Korean and other women forced to work in Japanese military brothels. The publisher deleted the testimony of one of these former so-called comfort women, and instead repeated the official line that there is no written evidence that they had been forcibly abducted.

Intense attention has also fallen on a statement that Abe is expected to release on the Aug. 15 anniversary of the war’s end, and whether it will contain the same language as statements issued by previous prime ministers on the 50th and 60th anniversaries. Those statements expressed remorse for Japan’s "colonial rule and aggression" that caused "tremendous damage and suffering to the people of many countries."

So far, Abe has refused to specify what his anniversary statement will say. Analysts say he appears torn between more moderate voices and his political base on Japan’s far right, many of whom believe their nation was unjustly painted as the villain by the victorious Allies after the war. Those divisions have appeared in a 16-member advisory panel appointed by Abe earlier this year to help him draft the statement. The panel has had heated debates over whether to use the word "aggression" to describe Japan’s wartime expansion, according to minutes of a recent meeting.

Many in the United States also want Abe to come clean on history issues during a visit later this month to Washington, where he will become the first Japanese leader to address a joint meeting of Congress. Some veterans and Korean-Americans opposed inviting Abe to speak unless he promised to admit responsibility for Japan’s wartime misdeeds.

Though these demands were ultimately brushed aside, many in the United States and Asia will be paying close attention to what Abe says to Congress as a possible foretaste of his 70th anniversary statement.

U.S. analysts and policymakers say they hope Abe makes a clear repudiation of Japan’s wartime conduct. Failing to do so, they fear, may undermine his efforts to take a leading role in Asian security by easing Japan’s self-imposed restraints on its military, something that is warmly welcomed by Washington at a time when it faces a rising China, military budget cuts and new crises in the Middle East.

Disputes over history "threaten to reduce Asian appetites to work more closely with Japan," wrote Richard Fontaine, president of the Center for a New American Security in Washington. "They also provide an opportunity for China to rally regional opposition" to a larger Japanese security role "based on a shared sense of grievance."

Within Japan, Abe’s inability to express a heartfelt repentance is often contrasted with the stronger displays of contrition by members of the imperial family. In February, the emperor’s son, Crown Prince Naruhito, the 55-year-old heir to the Chrysanthemum Throne, appeared to chide Abe when he said it was necessary to "correctly pass down" history to future generations.

At the same time, Akihito’s visit to Palau appeared to fall in line with Abe’s efforts to raise Japan’s profile. On the first evening of the two-day trip, the emperor and empress stressed Japan’s close ties to the region during a banquet with the president of Palau, Tommy Remengesau, and the leaders of two other Pacific island nations, the Federated States of Micronesia and the Republic of the Marshall Islands.

All three of these nations were Japanese colonies before the war, and have received millions in economic aid after 1945 that has helped them build roads, bridges and airports.

Before departing on Thursday, the emperor said he wanted to "mourn and pay tribute to both the Japanese and Americans who perished in the region." But he also said he hopes his visit "will contribute to the further development of the friendly cooperative relations that our nations have forged.

Martin Fackler, New York Times