WASHINGTON (Kyodo) U.S. Ambassador John Roos will likely attend the annual Aug. 6 ceremony in Hiroshima to commemorate the 1945 atomic bombing, becoming the first U.S. government representative to be sent to the event, sources close to bilateral relations said Tuesday.

The U.S. is making final arrangements for his attendance, the sources said. President Barack Obama's desire to push for a world without nuclear weapons is believed to be behind the move.

Roos visited Hiroshima last October and toured Peace Memorial Park and the A-Bomb Dome.