BERLIN (Reuters) - Schools and kindergartens will be shut in most German states until after the Easter holiday in April, a measure designed to slow the spread of the coronavirus.

"The challenge is immense," Bavarian state premier Markus Soeder told a news conference.

"As of next Monday the schools and children's day-care centers will be closed - this will apply provisionally until the end of the Easter holidays, that is until April 20," he said, adding the authorities would then take stock of the situation.

Ten other states, including North Rhine-Westphalia, Germany's most populous region, have taken similar measures as the number of confirmed cases across the nation jumped by 671 to 3,062.

In Berlin, schools and day-care centers will gradually shut down starting on Monday and public transport will be reduced to a minimum, Mayor Michael Mueller said.

Calls have been growing for Germany to follow the bulk of its European neighbors in shuttering schools to help slow the spread of the virus. The country's highly devolved system means only regional governments can make that call.

Health Minister Jens Spahn urged hospitals in a letter to recall retired medical staff and retrain them in case medical facilities become overwhelmed by a large number of patients needing hospitalization, Bild newspaper reported.

He also urged hospitals to be ready to prepare medical students for a possible role in caring for coronavirus patients.

Germany's states have agreed that public gatherings of more than 100 people should not go ahead. Municipal elections on Sunday in the southern state of Bavaria would go ahead.

(Reporting by Thomas Escritt and Paul Carrel; Writing by Joseph Nasr; Editing by Alison Williams and Edmund Blair)