Several regions in southern and western Russia issued warnings about possible drone attacks, and four southern airports suspended operations over safety concerns early on Tuesday.

Temporary restrictions at the airports in Vladikavkaz, Grozny and Magas affected arriving and departing flights, the Russian air transport agency Rosaviatsia said.

Another southern town, Mozdok, home to a military airfield, also closed its airspace, North Ossetia Governor Sergei Menyailo posted in his channel on the Telegram messaging platform.

The leaders of three Russian regions — Voronezh, North Ossetia and Kabardino-Balkaria — said they faced threats of drone attacks.

Residents should take cover inside and stay away from windows, Voronezh Governor Alexander Gusev said. They might also experience slower phone and internet connections, the regional officials added.