TOKYO, November 7, 2009 (AFP) - US President Barack Obama has delayed his visit to Japan next week by one day, a Japanese foreign ministry official said Saturday, following a deadly shooting at a military base in Texas.

Japanese national broadcaster NHK and Jiji Press reported that Washington had asked Tokyo to change the schedule for the two-day visit to allow Obama to attend a memorial service for the 13 people killed in Thursday's shooting.

Obama had been due to arrive for his first trip to Japan on Thursday for talks with Prime Minister Yukio Hatoyama and to meet Emperor Akihito.

"The (US) government has requested a delay," a foreign ministry official told AFP, adding that the Japanese government had agreed to the request.

Obama would now be arriving on Friday and stay until Saturday, the official said. A meeting scheduled for Friday with Hatoyama would go ahead as planned, Kyodo News reported, quoting an unnamed foreign ministry source.

White House spokesman Robert Gibbs earlier told reporters in the United States that Obama would attend a memorial service for those killed when a Muslim army doctor went on the rampage at the Fort Hood base.

"When a service is scheduled the president will attend," he said, adding only that the timing of the memorial would be scheduled "for the convenience of the families."

The man accused of the shooting, Major Nidal Malik Hasan, 39, was a psychiatrist and specialist in combat stress who had been about to deploy to Afghanistan against his wishes.

Thirty people were also wounded in the deadly rampage.

Obama has led the United States in mourning and has ordered flags to fly at half-mast at the White House and federal buildings, as US troops around the world held a minute's silence to mourn the dead.

The US president's visit to Japan is likely to be dominated by a row over an American military base on the southern island of Okinawa.

Residents have long complained about the base and plans to relocate it to another part of the island, while Hatoyama's government, which came to power in September, has promised to review the issue.

Hatoyama on Friday said he did not plan to make a decision on the base before Obama's visit.

While the Japanese leader has promised to review a pact under which a new US base would be built on the island, Washington has insisted Tokyo stick to the agreement.

The issue has clouded ties ahead of Obama's visit.

Washington and Tokyo have been close allies in the post-World War II era, and the United States has about 47,000 troops based in Japan, more than half of them on Okinawa, where their presence has often rankled local residents.

Hatoyama, who campaigned on a promise to review ties with Washington, has suggested that the US Marine Corps Futenma Air Base, currently located in a crowded urban area, may have to be moved off Okinawa altogether, or even out of Japan.

His government has stressed that while it values the US-Japan security alliance, it wants its relationship to be less subservient than under conservative governments that ruled Japan for more than half a century.

Japan has also said it will end a naval refuelling mission backing the NATO-led Afghanistan campaign when its mandate expires in January, but that it would instead boost aid to the war-torn country.