Metro Transit suspended service of all bus and light-rail service between 11 p.m. and 4:30 a.m. beginning Tuesday in an effort to stem the spread of the coronavirus.

The transit agency, which serves the Twin Cities metro area, said Monday the unusual move was necessary so it can focus its "limited resources" when demand for service is at its greatest. This is the first time in at least a decade transit service has been curtailed in this way.

"It is also an important safety measure as the region and nation works through this pandemic," Metro Transit General Manager Wes Kooistra said in a news release.

The move comes as transit ridership in the Twin Cities continues to decline, and as other transit agencies nationwide consider similar cutbacks in the wake of an unprecedented pandemic. Earlier this week, the Washington Metropolitan Area Transit Authority curtailed transit service in the nation's capital.

Overall ridership on Metro Transit buses, commuter trains and light rail dipped last year by 3%, with local bus routes taking the biggest hit, declining 5%.

Ridership on the system's buses and trains is at its lowest overnight, meaning "the fewest number of people will be impacted by the loss of service," Metro Transit said. Green and Blue Line trains already shut down between 2 and 4 a.m. nightly.

In addition, a persistent shortage of bus drivers is expected to worsen as the virus spreads among Metro Transit's ranks, and as parents take time off because of school closures.

Metro Transit also noted that 60% of the "biohazard incidents" occur at night — including bodily fluids from nighttime passengers that pose "unhealthy conditions in regular times; during a pandemic event, those health concerns increase." The closures will give Metro Transit more time to clean and disinfect buses and trains.

Reports have surfaced in recent days that bus and train operators have been given just 10 disinfectant wipes to clean their vehicles.

In addition, Metro Transit has advised passengers to take the bus and light rail during the day and early evening only for essential trips, and to practice social distancing while on board, if possible.

It's unclear when regular service will resume. "We will continue to evaluate the right thing to do to make sure our service is safe," said Metro Transit Spokesman Howie Padilla.

Metro Transit police officers will continue their overnight shifts.