MOSCOW (AFP) — Russia said Friday it had seen an increase in United States drone flights over the Black Sea and vowed to respond, warning they could lead to “direct confrontation” with North Atlantic Treaty Organization (NATO).

It comes five days after the Kremlin accused the US of being responsible for a Ukrainian missile attack on the annexed Crimean peninsula that killed four people, an incident that sent tensions soaring.

Russia’s defense ministry noted an increased number of “US strategic unmanned aerial vehicles over the waters of the Black Sea” and accused Washington of using the flights to help Ukraine strike Russian targets.

“This demonstrates the increasing involvement of the United States and NATO countries in the conflict in Ukraine on the side of the Kyiv regime,” it said.

“Such flights multiply the likelihood of airspace incidents with Russian Air and Space Force aircraft, which increases the risk of a direct confrontation between the alliance and Russia,” it added.

Defense Minister Andrei Belousov has instructed the army “to submit proposals on measures for an operational response to the provocations,” the defense ministry said.

The US routinely carries out drone flights over the Black Sea, operations that it says are conducted in neutral airspace and in accordance with international law.

In March 2023, Russia intercepted a US MQ-9 Reaper drone over the Black Sea, raising fears of direct confrontation between the two nuclear powers at a time of increased tension over the Ukraine conflict.

Meanwhile, a Ukrainian drone hit a petrol depot early Friday setting it on fire, a Russian regional governor said, adding that the strike took place hundreds of miles from the border.

Maxim Yegorov, governor of the Tambov region in central Russia, said the strike happened at 4:35 a.m. 

“A small fire broke out and it has been contained,” he said on messaging app Telegram. “There are no victims.”

Russia’s defense ministry, meanwhile, said it had “intercepted” 25 Ukrainian drones overnight, without mentioning the Tambov region.

In the western Bryansk region, governor Alexander Bogomaz said a drone had been downed but its debris “partially destroyed the roof of an administrative building.”

Ukraine, which has been facing a Russian offensive for over two years, regularly launches attacks targeting Russian energy and defence sites in response to strikes on its territory.