Updated

The nuclear-powered U.S. aircraft carrier USS George Washington arrived Thursday at its new home port just south of Tokyo, welcomed by a mix of cheering crowds and protesters.

The giant warship, which will replace the USS Kitty Hawk, docked at its new base in Yokosuka to shouting supporters and a brass band.

But protesters on shore and in a small flotilla of boats in the harbor demonstrated against the deployment, which some say poses a nuclear risk to Japan's capital.

The George Washington, which can carry a crew of up to 5,600 and 70 aircraft, will become the U.S. Navy's only carrier with a home port outside of the United States. The Kitty Hawk is to be decommissioned.

The demonstrators say the ship poses a threat to Tokyo because of the possibility of an accident in its nuclear reactor. They also are opposed to the increase in sailors who will be deployed to Yokosuka as a result of the ship swap, and say the carrier could make Yokosuka a target if hostilities break out between the United States and another country.

But Donald Winter, the U.S. secretary of the Navy, said the deployment of the ship demonstrates the U.S. commitment to its alliance with Japan and the U.S. 7th Fleet, which is based here.

"The 7th Fleet serves to defend Japan and deter war throughout the region," he said in a welcoming ceremony. "By providing one of our newest and most capable carriers, the George Washington, to the 7th Fleet, we are demonstrating our commitment to the U.S.-Japan alliance."

A statement by Japan's new Foreign Minister Hirofumi Nakasone also welcomed the carrier, but noted the Japanese concerns over a nuclear accident.

"We will continue to do all we can to assure that it is safe," Nakasone said.

The Navy says that upgrading to the George Washington will give the 7th Fleet greater range and better striking capabilities.

Along with the 7th Fleet, about 50,000 U.S. troops are deployed throughout Japan under a mutual security pact.

The Kitty Hawk, which is to be decommissioned, was conventionally powered and the deployment of the George Washington has raised concerns among anti-nuclear groups, who say it should not be located so close Tokyo, which lies about 30 miles to the north.

Such concerns were heightened when the U.S. Navy disclosed in early August that the USS Houston, a submarine, had leaked water containing radiation during several calls to Sasebo and Okinawa, in southern Japan, and Yokosuka between July 2006 and April 2008.

A Navy investigation found the leak posed no danger to Japan.

"We should not have a nuclear reactor, surrounded by ammunition and highly flammable jet fuel, located right outside of our most populated city," said Masahiko Goto, a local lawyer who has led protests against the ship.

Concerns over safety were also raised after a fire broke out aboard the carrier in May. The fire, which is believed to have been caused by smoking in an unauthorized area, resulted in dozens of injuries and an estimated $70 million in damage.

The ship's commanding officer and executive officer were relieved of duty.

Its new executive officer, Capt. Karl O. Thomas, said he was aware of the demonstrations.

"People can speak what they want to speak," he said. "If people want to protest, it is their right to do so."

He added, however, that the U.S. nuclear fleet has an "unblemished record" and said the safety concerns were unnecessary.