An independent newcomer backed by Prime Minister Shinzo Abe's government defeated the anti-U.S. base incumbent in the Nago mayoral election Sunday, an outcome which could give impetus to the central government's controversial plan to transfer an air base to the southern Japan city.

Taketoyo Toguchi's victory in a two-man race against Susumu Inamine is also expected to deliver a blow to the anti-base campaign of Okinawa Gov. Takeshi Onaga whose term will expire in late 2018.

Toguchi, a 56-year-old former Nago city assembly member known to be supportive of the base transfer, sought to divert voters' attention from the base issue and promised measures to spur the sluggish local economy during the election campaign.

On the base transfer issue, Toguchi told reporters after the election he will "closely monitor" the progress of a lawsuit Okinawa Prefecture has filed against the central government to block the U.S. base relocation.

A senior lawmaker of Abe's Liberal Democratic Party said voters apparently welcomed Toguchi's pledge to focus on improving the local economy.

"We have gained momentum toward the Okinawa gubernatorial election later this year," the lawmaker said.

The latest election is seen as a prelude to the Okinawa gubernatorial election, a crucial test for Onaga who was elected in November 2014 on a platform of opposing the plan to relocate U.S. Marine Corps Air Station Futenma.

Inamine, 72, also an independent, has campaigned against the Futenma transfer to a coastal area of Nago from another part of the island prefecture, gaining support from the Okinawa governor and most opposition parties.

Inamine told reporters he did his best in drawing voters' attention to the problem of allowing the base construction, but Toguchi "evaded the issue."

Onaga, who monitored the progress of vote counting with Inamine's supporters, did not clearly say how the election outcome would affect his stance on the base issue.

"I would like to consult (people concerned)," he said without elaborating on his plan for the gubernatorial election.

Takashi Shinohara, the head of the election campaign committee at the Democratic Party which backed Inamine, said the party takes the outcome seriously and will "use the experience for the future."

Toguchi garnered 20,389 votes while Inamine gained 16,931, according to the local election committee. Turnout was 76.92 percent, up slightly from 76.71 percent in the 2014 election.

Okinawa hosts the bulk of U.S. military facilities. Accidents involving U.S. military aircraft and crimes involving U.S. personnel have angered Okinawa residents, but gaining more economic support from the central government has also been a key issue in local elections in the prefecture.

Onaga has resorted to various measures, including legal actions, to stop the central government from transferring the Futenma base from a crowded residential area of Ginowan to the less populated Henoko coastal area of Nago. The move has slowed progress, but construction work to build a new facility in the Henoko area is now under way.

People in Nago have been divided over the issue, with some tired of the continuing clashes between the central and local governments, which have left the issue stalled.

Experts say Toguchi's win reflects voters' high expectations for measures to prop up the local economy and does not necessarily suggest that more Nago residents are willing to accept the base transfer.

It is the sixth mayoral election for Nago citizens since Henoko emerged as the destination for the relocation after the Japanese and U.S. governments agreed on the return of the land for the Futenma base in 1996. Inamine is serving his second four-year term as mayor.

The central government has maintained that the current relocation plan is "the only solution" for removing the dangers posed by the Futenma base, which is situated close to schools and homes, without undermining the perceived deterrence provided by American troops under the Japan-U.S. alliance.