Metro’s fleet of buses will be temporarily reduced by 10 percent while safety officials conduct emergency inspections. (Robert Thomson/The Washington Post)

Metro has pulled 164 buses — 10 percent of its fleet — from service for emergency inspections after two recent incidents in which the engines cut off suddenly while the buses were moving.

According to a statement the agency issued Wednesday night, two drivers in the past week have reported that their bus engines cut off suddenly. In both instances, Metro said, the bus was traveling at less than 10 miles per hour.

The malfunctions resulted in two minor injuries, after the bus’s brakes suddenly engaged and the bus jerked to a stop, the agency said.

One incident occurred on March 22 and the other Wednesday. Both buses were part of a fleet manufactured by the New Flyer company in 2015 and 2016. The buses are all 40-foot compressed natural gas models, the agency said.

The buses will remain out of service until Metro and the manufacture figure out what happened.

“We are taking this action, putting safety first, until we fully understand what caused these engines to cut off unexpectedly,” Chief Safety Officer Pat Lavin said in the statement. “While we understand there may be some customer inconvenience as a result of this action, safety must trump service.”

Similar problems were reported last year, when 105 hybrid buses manufactured by NABI were pulled from service due to mysterious mid-motion engine shut-offs.

In November, those buses were deemed safe, and were returned to service.

Metro said the buses remain under warranty.

“New Flyer is sending a team of experts to participate in the investigation,” Metro said. “The buses will remain out of service until the cause of the engine problem is determined.”

Metro officials said they will be able to limit the impact of the reduced fleet in the short-term by using 80 older-model “reserve” buses that are kept in circulation to help fill gaps when newer buses need repairs.

Still, Metro said, the reserve vehicles won’t be able to completely make up for the loss.

“Bus customers may notice some slightly longer wait times between buses,” Metro said.

And bad news for riders affected by the delays: “Metro’s Rush Hour Promise will not apply to bus delays resulting from the safety checks,” the agency said.