U.S. President Barack Obama paid moving tribute to atomic bombing victims, reaffirmed the U.S.-Japan security alliance and friendship between both nations and called for the elimination of nuclear weapons in a historic and emotional visit to Hiroshima on Friday.

Obama did not, however, include an apology for the dropping of the atomic bomb, which some in Japan and abroad had sought.

In a solemn ceremony, Obama — the first sitting U.S. president to visit the once-destroyed city — along with Prime Minister Shinzo Abe, arrived at Hiroshima Peace Memorial Park late Friday afternoon to bright sunshine that gradually gave way to a cool evening. Thick crowds jammed the periphery of the park, but it was otherwise quiet as Obama and Abe toured the Peace Memorial Museum and laid wreaths at the cenotaph.