The US Navy has fired the captain of the first US nuclear-powered aircraft carrier to be stationed abroad after a fire onboard hurt dozens of sailors and raised alarm in host Japan.

The USS George Washington is set to arrive in late September in Yokosuka, a naval hub near Tokyo, despite public protests in the only nation to have suffered nuclear attack.

The US Navy, releasing details of an investigation, said that a fire in May in waters off South America was caused when crew smoked near improperly stored flammable liquids.

A Navy statement on Wednesday said it was relieving Captain David C. Dykhof as commanding officer due to "a loss of confidence in his ability to command and his failure to meet mission requirements and readiness standards."

One sailor suffered first- and second-degree burns, while another 37 were treated for minor injuries, the Navy said.

The carrier needed 70 million dollars in repairs at a dockyard in San Diego, delaying its arrival in Japan, it said.

US diplomats and military officials visited the Japanese foreign ministry Thursday to explain the incident and said that the fire did not affect the safety of the nuclear equipment.

Shinichi Nishimiya, head of the North American affairs section, said he regarded the US investigation as "thorough and objective," according to a foreign ministry statement.

He said the punishment against the commanding officer showed US sincerity in enforcing discipline, although he urged US officials to take measures to prevent another incident, the statement said.

Japan agreed to accept the USS George Washington despite objections from residents around the Yokosuka base either opposed to nuclear weapons in principle or concerned about nuclear accidents.

Japan relies on nuclear technology for one-third of its electricity needs but has seen a series of accidents at plants that have dented confidence in safety.

The USS George Washington will replace the diesel USS Kitty Hawk, which is being retired from service.

The United States argued that it must deploy its best carrier in Yokosuka due to East Asia's tense security situation.

The United States, which dropped two atom bombs on Japan at the end of World War II, is now the closest ally of the Asian economic power and deploys more than 40,000 troops in the country.

But relations have recently been strained by a series of crimes committed by US servicemen in Japan.