Japan marked the 71st anniversary of the U.S. atomic bombing of Hiroshima on Saturday as its mayor urged world leaders to follow in U.S. President Barack Obama’s footsteps and visit, and ultimately rid the world of nuclear arms.A peace bell tolled at 8:15 a.m. (2315 GMT on Friday), the time a U.S. warplane dropped the bomb. About 50,000 participants including aging survivors and dignitaries held a moment of silence at a memorial ceremony in the western Japanese city.

Mr. Obama this year became the first incumbent U.S. President to visit Hiroshima, and he urged nuclear powers, including his own, to have the courage to escape the logic of fear and pursue a world without nuclear weapons.“The President’s words showed he was touched by the spirit of Hiroshima, which refuses to accept the ‘absolute evil’,” the mayor, Kazumi Matsui, told the crowd, referring to the weapons.

The United States dropped the bomb on Hiroshima on Aug. 6, 1945, killing thousands of people instantly and about 140,000 by the end of that year.U.S. forces dropped another atomic bomb on the southern city of Nagasaki on Aug. 9. Japan surrendered six days later.“I once again urge the leaders of all nations to visit the A-bombed cities,” Mr. Matsui said as cicadas buzzed away under the mid-summer sun.

“As President Obama confirmed in Hiroshima, such visits will surely etch the reality of the atomic bombings in each heart.”At the ceremony, Prime Minister Shinzo Abe pledged his determination to work toward a world free of nuclear arms.“We must not have the tragic experience of Hiroshima and Nagasaki 71 years ago repeat itself,” Mr. Abe said.“It is the responsibility of those of us who live in the present to keep on working without cease toward that aim.”

U.S. Republican presidential nominee Donald Trump has said he would consider letting Japan and South Korea build their own nuclear weapons, rather than rely on the United States for protection against North Korea and China.But Tomomi Inada, Japan’s new Defence Minister and an Abe ally, said on Wednesday she did not believe Japan should consider possessing nuclear weapons.North Korea has conducted four nuclear tests, the latest one in January. It has also conducted a string of tests of various missiles this year.

On Wednesday, it launched a ballistic missile that landed in the sea in Japan’s exclusive economic zone for the first time.

Ending days of suspense, Republican presidential nominee Donald Trump on Saturday endorsed his party’s two stalwarts House Speaker Paul Ryan and Senator John McCain for re-election and vowed to make Republicans a “big tent” party as was under ex-president Ronald Regan.

“In our shared mission to make America great again, I support and endorse our Speaker of the House Paul Ryan. We need unity. We have to win this election. This is truly one of the most important elections in my lifetime,” Mr. Trump said at an election rally in Mr. Ryan’s home state of Wisconsin.Over the past few days, Mr. Trump had refused to endorse either Mr. Ryan and Mr. McCain fueling speculations that all is not well among the Republicans and the party is not united ahead of the crucial November general elections.

While Mr. Ryan is expected to easily sail through his House seat, Mr. McCain is facing a tough battle from the Arizona Senate seat.“While I’m at it, I hold in the highest esteem Senator John McCain for his service to our country in uniform and in public office and I fully support and endorse his re-election,” Mr. Trump said amidst cheer from supporters.“This campaign is not about me or any one candidate, it’s about America. I understand and embrace the wisdom of Ronald Reagan’s big tent within the party,” Mr. Trump said.

“I need a Republican Senate and a House to accomplish all of the changes that we have to make. So I embrace the wisdom that my 80 per cent friend is not my 20 percent enemy,” he said at the election campaign in Green bay in Wisconsin.“Working hand-in-hand we will grow our majority in the House and in the Senate. Arm-in-arm we will rescue the nation from the Obama—Clinton disaster that has bled our country dry and spread terrorism unabated across the world,” Mr. Trump said.Later in a fund raising email to his supporters, Mr. Trump alleged that the Democrats and the mainstream media are doing everything they can to divide the Republican party.

“We must rise above their dirty tactics and prove that only the Republican Party is offering the ideas and solutions that can truly fix America,” he said.“It’s time to unite our Party and deny a third term of Obama. I have officially endorsed Paul Ryan —— and together, we will fight for you, and together we will Make America Great Again!” Mr. Trump said.