U.S. President Barack Obama will cite his country’s “moral responsibility” to lead efforts to create a world free of nuclear weapons when he visits Hiroshima next week, one of his top speechwriters said Wednesday.

Obama, who plans to make brief remarks during his visit to the city, the site of an atomic bomb attack during World War II, will “absolutely” touch on the United States’ moral responsibility as the only nation to have used a nuclear weapon during a time of war, Deputy National Security Adviser for Strategic Communications and Speechwriting Ben Rhodes told Kyodo News in an interview.

“We have said that we have a unique and moral responsibility as the only country that’s used a nuclear weapon to prevent the future use of nuclear weapons,” Rhodes said.

“There was a terrible loss of life in Hiroshima and Nagasaki, and in many other countries during World War II.”

Rhodes was the writer of a landmark speech Obama delivered in Prague in 2009 in which he expressed resolve to seek a world without nuclear weapons.

Asked what kind of message Obama will send from Hiroshima, Rhodes said, “We have to recognize the awful toll that atomic weapons, nuclear weapons, take on people.”

The United States dropped atomic bombs on Hiroshima and Nagasaki in August 1945 in the final stage of World War II. The death toll in the two cities by the end of that year exceeded 210,000 people.

Obama will on May 27 become the first sitting U.S. president to visit Hiroshima after attending a Group of Seven leaders’ summit in Mie Prefecture.

Rhodes implied Obama will not apologize for the nuclear attacks on Japan or revisit President Harry Truman’s decision to drop atomic bombs on the two Japanese cities.

“It’s very important that the Japanese people understand that Americans are very proud of the generation that served in World War II, under difficult circumstances,” Rhodes said.

According to public polls and the U.S. media, many Americans including war veterans believe the atomic bombings forced Japan to surrender in the war earlier than it would otherwise have done, saving the lives of many American soldiers as a result.

“There is a way in which we can acknowledge history, without revisiting decisions or second-guessing leaders in that moment,” Rhodes said.

White House officials said Obama is expected to speak for several minutes at Hiroshima Peace Memorial Park near ground zero, and some atomic-bomb survivors may be in the audience.

Under Obama, the United States has led international efforts to reduce the role of nuclear weapons. A biennial Nuclear Security Summit was launched under his initiative in 2010, with the U.S. and other world powers reaching a deal with Iran in 2015 aimed at curbing Tehran’s nuclear programs.

Rhodes expressed dissatisfaction, however, with what he said was a lack of Russian cooperation in efforts to reduce nuclear stockpiles.

“The Russians became less interested in arms control discussions,” he said. “Part of what going to Hiroshima can do is create and instill that sense of urgency, going forward, that keeps this front and center for leaders,” Rhodes said.