The Defense Ministry said Friday it expects the U.S. military to suspend flights of its CH-53E transport helicopters in Okinawa for an “indefinite period” after a crash-landing days earlier left the ruling Liberal Democratic Party reeling ahead of the Oct. 22 Lower House election.

The move came even though the U.S. Marine Corps in Japan said in a press release Thursday that it had ordered a “96-hour operational pause” for all CH-53E helicopters stationed in the prefecture in a bid to ensure the readiness and “the safe conduct of our aviation community.”

Defense Minister Itsunori Onodera, however, said that he had agreed with the deputy commander of U.S. Forces Japan during talks in Tokyo on Thursday that no timeline had been set for the operational pause.

“I asked (Maj. Gen. Charles Chiarotti) that the period (of the pause) would be until safety is ensured, and the deputy commander said that’s right,” Onodera told reporters.

The accident occurred Wednesday afternoon, when a CH-53E caught fire in midair during a training flight and burst into flames, making an emergency landing in Takae in the village of Higashi near the U.S. Northern Training Area on Okinawa’s main island.

The CH-53E is a large transport helicopter used by the U.S. Marines that can carry up to 55 personnel in addition to seven crew members. The helicopter involved in Wednesday’s incident was based at Marine Corps Air Station Futenma.

None of the seven crew members or local residents was hurt, but the accident, the latest in a string of incidents involving U.S. aircraft in the southernmost prefecture — including the crash-landing of an Osprey aircraft off the main island in December — has heightened safety concerns among the local population.

Many Okinawans have long been frustrated with noise, crime and accidents connected to U.S. bases, with the prefecture hosting around 70 percent of the U.S. military’s facilities in Japan.

Prime Minister Shinzo Abe’s Liberal Democratic Party now faces an unexpected headwind in the Lower House election race, with the latest accident rekindling anger on Okinawa over the heavy U.S. military presence.

“We can’t avoid the impact” of the accident on the election, a senior official with the LDP’s Okinawa chapter said.

The emergency landing, which occurred the day after the start of election campaigning, came “at the worst time,” a senior official at the Prime Minister’s Office said.

Chief Cabinet Secretary Yoshihide Suga called Kumiko Nakamine, head of the Takae district, a few hours after the crash-landing and told her that the government was ready to provide any help needed and apologized for the trouble.

Abe expressed regret over the accident soon after hearing about it and directed officials to urge the U.S. side to conduct an investigation to determine the cause and take measures to prevent similar incidents.

Looming behind the quick government response has been the LDP’s defeat in Okinawa’s four electoral districts in the previous Lower House election in 2014.

With this month’s election looming, the government has tried to quickly address local concerns in an effort to minimize any repercussions from Wednesday’s incident.

While the U.S. military’s presence in Okinawa has a not been a major issue in the upcoming election, it could now end up hurting LDP candidates.

The party has stuck to its plan to relocate the Futenma base from a crowded residential district in Ginowan to the less populated Henoko district of Nago — even as Okinawa Gov. Takeshi Onaga insists it should be moved outside the prefecture to reduce the local burden of hosting U.S. bases.

The Constitutional Democratic Party of Japan has pledged to review the plan, while the Japanese Communist Party and the Social Democratic Party are opposed to its relocation within the prefecture.

Kibo no To (Party of Hope) and Nippon Ishin no Kai both seek to reduce the burden and review the Japan-U.S. Status of Forces Agreement (SOFA) that governs the handling of U.S. service personnel in Japan.

“One wrong move could have triggered a serious accident involving civilians. This incident adds to concerns of the people in the prefecture who live side by side with U.S. bases,” Onaga said in a statement addressed to Onodera.

The statement also said that locals “cannot help but feel strong doubts over the U.S. military’s aircraft maintenance and safety measures” and demanded that CH-53Es be grounded until the cause of the accident is identified and “effective” preventive steps are taken.

Protesters on Friday gathered around the site of the accident and in front of U.S. bases in the prefecture, calling for a reduction in Okinawa’s base-hosting burden.

The same day, four Self-Defense Force members with expertise in helicopters visited the accident site to gather information on the incident.

But it remains unknown to what extent Japan can get involved in probing the accident’s cause, as Japanese authorities do not have the power to search or seize U.S. military assets without consent under SOFA.

Onodera, however, told reporters that the SDF experts are dealing with the issue, so the investigation will not be a mere formality.