Authorities in four Russian regions bordering Ukraine and in Russian-controlled Crimea announced they were stepping up security measures on Monday over what they said were "possible provocations" from the Ukrainian side.
Moscow, which sent thousands of troops into Ukraine in what it calls a "special military operation", has accused Ukraine of targeting its border regions, including by striking a fuel depot in the city of Belgorod earlier this month.
The authorities in the Belgorod, Voronezh, Bryansk and Krasnodar regions and in Crimea said they were boosting security and urged citizens to be more vigilant. Another region bordering Ukraine, Kursk, was the first to announce similar measures on Sunday.
"During the special operation by Russian forces on the territory of Ukraine, the Donetsk People's Republic and Luhansk People's Republic, issues pertaining to anti-terrorist security have become more pressing due to possible provocations from Ukrainian nationalists," said Alexander Gusev, the governor of the Voronezh region, which shares a border with Ukraine's Luhansk region.
Vyacheslav Gladkov, the governor of the Belgorod region, said it would implement additional security measures until April 25 to counter what he called terrorist threats. The region borders Ukraine's Sumy, Kharkiv and Luhansk regions.
Gladkov said the population should steer clear of crowded public places, carry identity documents on them, have an evacuation plan and pay special attention to strangers and unusual vehicles near residential buildings.
The Bryansk region, which shares a border with Ukraine's Sumy and Chernihiv regions, said it was also on alert for terrorist threats.
The governors of the Krasnodar region, across the Sea of Azov from east Ukraine, and of Crimea, which Russia annexed from Ukraine in 2014, said they were raising "terrorism alerts" and would strengthen law enforcement in several districts.
On Sunday, the governor of the Kursk region, Roman Starovoit, said police and military officers would set up checkpoints, less than a week after border guards allegedly came under fire in the region.
Russia sent tens of thousands of troops into Ukraine on Feb. 24 in what it called a special operation to degrade its southern neighbour's military capabilities and root out people it called dangerous nationalists.
Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw its forces.
(Reporting by Reuters; editing by Guy Faulconbridge and Alistair Bell)
