A Marine Corps jet fighter crashed into the Pacific ocean about 120 miles southeast of Iwakuni, Japan, on Wednesday, the 75th anniversary of the attacks on Pearl Harbor.

The unidentified pilot, assigned to the 1st Marine Aircraft Wing, ejected from the F/A-18 Hornet around 6:40 p.m. local time while conducting regular training, according to III Marine Expeditionary Force public affairs.

Search and rescue efforts are underway, and the cause of the mishap is being investigated.

There were no indications as to why the F/A-18 crashed, Marine Commandant Gen. Robert Neller told reporters after an event Wednesday morning at the Newseum in Washington, D.C.

Neller expressed hope that the Hornet pilot will be rescued.

“I’m not going to say we’re done until we’re done – and we’re not done; we’re going to keep looking for this pilot,” Neller said.

While the number of major mishaps is up over the last few years, it is not “completely statistically off the wall,” he said.

Marine pilots are also getting four more flight hours than they did last year, but the Corps’ plan to increase flight hours and flyable aircraft is not going as quickly as the service would like, Neller added.

“We are in a pretty tough place and we had to develop a plan and our plan is happening, but it’s not happening fast enough,” he said. “The bottom line is we’ve got to recapitalize aviation. We need to replace our airplanes. We’ve got to get better parts support. We’ve got to get more hours so if there is a human factor involved in this, we make sure that the air crew have been flying so we drive that down.”

The U.S. military is currently operating on a temporary spending measure instead of a budget, so the Marine Corps does not yet have money to give pilots more flight hours in fiscal 2017. The continuing resolution funding the military lasts until March.

One problem with a continuing resolution is that if Congress ultimately passes a budget with more money than the temporary spending measure, the Marines will have less time to spend the money, Neller said.

“You can only fly so much and you can only let so many contracts,” he said. “I trust the Congress. I think the new administration clearly understands what the situation is. The good news is we got money and we’ll continue to operate and train. The forces that are forward deployed, they’re flying a lot of hours and so far they have been very effective and very safe.”

Today’s crash follows on the heels of several recent accidents involving the aircraft. In October, an F/A-18C crashed near the end of a training flight at the Marine Corps Air Ground Combat Center in Twentynine Palms, California – the pilot ejecting safely

Just three months before, another F/A-18C warplane went down during a Twentynine Palms training mission, killing the pilot.

Two Marine F/A-18 Hornets collided during a daytime training mission near San Diego in November, with both pilots surviving.

A Blue Angels pilot was killed in a crash in June, shortly after takeoff in Smyrna, Tennessee. In May, two F/A-18F Super Hornets collided mid-air off the coast of North Carolina. Both of the planes’ pilots and flight officers ejected and were recovered.