Japanese PM Shinzo Abe has visited the US naval base at Pearl Harbor, where he offered "sincere and everlasting condolences" to the victims of Japan's attack on the base 75 years ago.
"We must never repeat the horrors of war again, this is the solemn vow the people of Japan have taken," he said.
Mr Abe was accompanied by US President Barack Obama, making the visit the first by the leaders of both countries.
Japan devastated much of the base, killing more than 2,400 Americans.
'An alliance of hope'
Mr Abe paid tribute to the men who lost their lives in 1941 at the naval base, many of whom remain entombed in the wreckage of the USS Arizona, sunk by the Japanese that day, and vowed reconciliation and peace.
"To the souls of the US servicemen who lie aboard the USS Arizona, to the American people, and all people around the world, I pledge that unwavering vow," he said.
The Japanese prime minister went on to praise the US for its efforts to mend relations with Japan following the war between the two countries, which ended shortly after the US dropped two atomic bombs on Japan in August 1945.
And he called the renewed alliance between the countries an "alliance of hope".
Mr Obama also paid tribute to the dead, saying that he had laid a wreath on "waters that still weep".
"That morning the ranks on those men's shoulders reflected them less than the courage in their hearts," he said.
He said he welcomed Mr Abe "in the spirit of friendship, in the manner Japan has always welcomed me".