SOFIA — Bulgarian health authorities have restored some lockdown measures following the rise of new coronavirus cases in the Balkan country.

Health Minister Kiril Ananiev on Monday ordered the mandatory wearing of protective masks in all indoor public places and announced stricter lockdown measures.

Bulgaria had imposed a two-month state of emergency between March and May and health authorities were initially successful in containing a virus outbreak. But with easing lockdown measures, the number of active cases rose by 640 between June 7 and June 22, to a total of 1,632.

The Black Sea nation, which relies heavily on tourism, started to reopen its resorts in hopes of salvaging the summer season, but the current virus spike is derailing those plans.

The first charter flight to Bulgaria this season that was bringing in Latvian tourists was cancelled Monday. The mayor of Bulgaria’s Black Sea town of Burgas, Dimitar Nikolov, added that a total of 150 Burgas-bound chartered flights scheduled for July had been cancelled.