By Mark Trevelyan

(Reuters) -Russia sent Tu-22M3 long-range bomber planes on a flight over the Baltic Sea on Wednesday, the defence ministry said, in the first such mission since Ukraine carried out a stunning June 1 attack on air bases in Siberia and the far north.

A number of Tu-22M3 and Tu-95MS bombers were destroyed or seriously damaged in those strikes, conducted by drones that were smuggled close to the airfields in trucks.

Russia regularly conducts heavy bomber flights as a show of strength and deterrence to its adversaries, but Wednesday's also appeared aimed at sending a message of business as usual despite the Ukrainian attacks.

The defence ministry said the Tu-22M3s flew for more than four hours over neutral waters of the Baltic, escorted for some of that time by fighter planes from foreign, presumably NATO, countries.

The Tu-22M3 and Tu-95MS, known to NATO respectively as Backfire and Bear-H, are part of a long-range aviation fleet that Russia has used throughout the war to fire conventional missiles at Ukrainian cities, defence plants, military bases, power infrastructure and other targets.

The Bear-H and the newer Tu-160M Blackjack are nuclear-capable aircraft which, alongside ground- and submarine-launched ballistic missiles, form part of Russia's strategic nuclear deterrent.

Deputy Foreign Minister Sergei Ryabkov said on Wednesday that Moscow's potential for nuclear deterrence against the United States had not suffered "any tangible damage" as a result of the Ukrainian attacks.

Ryabkov has previously said Russia would repair the damage from the strikes, although commercial satellite images show a number were clearly destroyed. The United States assesses up to 20 warplanes were hit, around half the number estimated by Ukrainian President Volodymyr Zelenskiy, and around 10 were destroyed, two U.S. officials told Reuters last week.

Ryabkov, without citing evidence, said Western countries had provided technical help to Ukraine when it came to targeting and transmission of real-time data, and this made them complicit.

"These countries, which have such capabilities, took this step, deliberately testing our patience and endurance - they encroached on the foundations of the concept of nuclear deterrence, not just with their irresponsible indulgence of the Kyiv regime, but by supplying this regime with key sensitive information," Interfax news agency quoted him as saying.

The United States has said President Donald Trump was not informed in advance of the Ukrainian operation, dubbed "Spider's Web," which Zelenskiy has said was 18 months in the planning.

(Reporting by Mark Trevelyan; Editing by Chris Reese)