TOKYO — Denny Tamaki was elected Sunday as the next governor of Okinawa prefecture in Japan, after a campaign focused on sharply reducing the U.S. military presence on the island.

Okinawa is home to about half the 54,000 U.S. troops stationed in Japan and houses the largest U.S. air base in the Asia-Pacific region. The U.S. military says its presence on the island is vital not only for the defense of Japan but also for keeping the peace in the entire region, from Taiwan and China to the Korean Peninsula and down to the Philippines.

But Okinawans feel that their small island bears an unfair burden of the U.S. military presence in Japan. They complain about the noise of low-flying aircraft and the dangers of accidents, as well as crimes committed over the years by members of the U.S. military. Some also feel that the presence of the bases could make their island a target in any regional military confrontation.

Tamaki, like previous governor Takeshi Onaga, who died in office last month, wants a fundamental reduction of the U.S. presence here, a stance that will add stress to the United States’ alliance with Japan. 

With 99 percent of ballots counted Sunday night, he had won 55 percent of the vote, with his main rival, Atsushi Sakima, who was backed by Japan’s ruling Liberal Democratic Party, winning 44 percent.

Tamaki is the son of an Okinawan woman and an American Marine, whom he has never met. He says that will stand him in good stead as he tries to negotiate with Washington as well as Tokyo.

The key issue is Marine Corps Air Station Futenma, which sits in the middle of residential areas in the city of Ginowan. There is a two-decade-old plan to relocate the base to a more remote site at Henoko in the north of the island and move nearly half of the 19,000 Marines on the island to bases  in Guam, Hawaii and Australia. The move has been delayed largely because of local opposition.

Tamaki opposes the expansion of the Henoko facility, known as Camp Schwab, and instead demands a more radical redistribution of U.S. forces to other parts of Japan or abroad.

The central government in Tokyo insists it has the constitutional right to decide on national security issues, and it wants to push ahead with the relocation plan. It won a legal battle against Onaga when he tried to block the move to Henoko.

But Tamaki’s victory spells another round of tough negotiations and potentially more legal battles over the relocation plan.

“I’d like to promise that I will build on Governor Onaga’s foundation,” he told a local television station shortly after Japanese media declared him the victor. “What people cannot accept is the relocation to Henoko, and I will firmly carry out the will of the people.”

Scott Harold, a senior political scientist at the Rand Corp., said Tamaki’s victory means that the Futenma issue is likely to remain a live one in Okinawan politics for some time. And until Tokyo and Okinawa reach an agreement, the Futenma base will stay where it is.

“The danger for the alliance of that is that an accident could occur in the Ginowan area, which could have substantial consequences for the Japanese government’s ability to elicit continued support or at least acquiescence from the Okinawan people for the U.S. force presence,” Harold said.

U.S. military bases take up nearly one-fifth of the land on Okinawa but also contribute to the local economy. The island receives significant compensation from the central government for hosting the U.S. military.

Sakima, Tamaki’s opponent, argued that the Futenma relocation should go ahead to ease the burden on Ginowan and free up land for development. 

The U.S. military has worked hard to improve its image on the island, with Marines giving up their free time to teach English to Okinawans or help clean up local beaches. 

It also throws open the doors to its bases for regular festivals that attract tens of thousands of people.

It has moved artillery training off the island and says it has taken as much aircraft training as it possibly can off the island to allay local concerns without undermining combat readiness. There are, for example, greater restrictions on parachute training operations, low-level flight and nighttime aircraft training operations than is typical in the United States, officials say.

But several incidents have damaged the military’s image, including the 1995 rape of a 12-year-old schoolgirl by three servicemen and a 2004 helicopter crash onto the grounds of a local university.

Akiko Kashiwagi contributed to this report.