TOKYO (REUTERS) - Prime Minister Shinzo Abe's visit to Pearl Harbour this month may not be the first by a sitting Japanese prime minister, but will be the first with a US president, his top government spokesman said on Thursday (Dec 8), trying to clarify confusion over the trip.

Mr Abe announced on Monday that he would join President Barack Obama on a Dec 26-27 visit to the site of the Japanese surprise attack 75 years ago that drew the United States into World War Two.

A foreign ministry official had said on Monday that Mr Abe would be the first incumbent Japanese leader to visit Pearl Harbour.

But media later said that back in September 1951, then-Prime Minister Shigeru Yoshida stopped by Pearl Harbour en route from San Francisco.

When asked about this, Chief Cabinet Secretary Yoshihide Suga told reporters that the government could not confirm exactly where Mr Yoshida visited.

"Then-prime minister Yoshida visited Honolulu in 1951 and at that time he honoured the war dead at the National Memorial Cemetery of the Pacific," Mr Suga said. "The scope of Pearl Harbour is broad and whether Prime Minister Yoshida visited there or carried out some ceremony cannot be confirmed."

"At any rate, the Arizona Memorial in Pearl Harbour was not built then and Prime Minister Abe will be the first incumbent prime minister to pray for the war dead there," Mr Suga said, referring to a memorial for US sailors and Marines killed in the attack. "He will also be the first to do so with an American president."

Mr Abe's visit to Pearl Harbour will come seven months after Mr Obama became the first serving US president to visit the Japanese city of Hiroshima, where the United States dropped an atomic bomb on in the closing days of the war in 1945.

The two leaders hope to showcase the strength of the security alliance between the two former wartime foes.