(Bloomberg) -- A third Russian airfield came under drone attack Tuesday after Moscow accused Ukraine of carrying out strikes against two bases used by its long-range bombers, the deepest retaliation on its territory since President Vladimir Putin ordered the invasion.

An oil storage tank caught fire after the drone strike at a Kursk region airfield, state-run Tass news service reported Tuesday, citing a Telegram post by local governor Roman Starovoyt.  

The incident followed attacks Monday on military bases in Russia’s Saratov and Ryazan regions that damaged two aircraft and killed three service personnel when drones crashed after being intercepted by air-defenses, according to the Defense Ministry in Moscow. The airfields are home to strategic aircraft capable of carrying nuclear weapons.

Ukraine hasn’t confirmed it carried out any of the attacks. The Saratov and Ryazan regions, southeast of Moscow, are at least 500 kilometers (310 miles) from the border between the two countries, while Kursk is about 100 kilometers from Ukraine. 

Russia fired air- and sea-launched missiles against energy and communications infrastructure in Ukraine after Monday’s attacks. Putin’s military has waged a campaign of missile and drone assaults against critical infrastructure in Ukraine in recent weeks aimed at cutting power, heating and water supplies to civilians during winter, prompting an international outcry and accusations that it is committing war crimes. 

How and Why Russia Is Using Iranian Drones in Ukraine: QuickTake

At an online briefing on Tuesday, Ukrainian air defense spokesman Yuriy Ihnat declined to comment on any role by Ukraine in the “mysterious explosions” in Russia.

Authorities are taking “necessary measures” to safeguard against possible Ukrainian attacks on Russian territory, Kremlin spokesman Dmitry Peskov told reporters on a conference call Tuesday.

The United Nations Security Council will meet Tuesday to discuss humanitarian issues in Ukraine at the request of “Western countries,” Russian deputy UN envoy Dmitry Polyanskiy said on Telegram. States at the meeting would also likely criticize the Russian strikes on Ukrainian infrastructure, he said.

The massive strikes are part of Russia’s plan to “crush Ukraine’s military potential,” Defense Minister Sergei Shoigu said Tuesday, according to the Interfax news service.

Russia has blamed Ukraine for a series of blasts at military facilities in Crimea, which Putin annexed in 2014. Russian state TV on Monday showed Putin driving along a flagship bridge linking Russia to Crimea across the Kerch Strait to inspect repairs to damaged road and rail links following an explosion in October. 

Ukrainian officials have mostly avoided claiming responsibility for such attacks, though they subsequently confirmed involvement in a strike that damaged Russian warplanes at a Crimean airfield in August.

“If something is launched into other countries’ airspace, sooner or later unknown flying objects will return to departure point,” Ukrainian presidential adviser Mikhailo Podolyak said on Twitter after Monday’s blasts. 

©2022 Bloomberg L.P.