British and German fighter jets intercepted a Russian aircraft flying close to Estonian airspace Friday, according to a statement from the UK's Royal Air Force (RAF).
It was the second such encounter this week, as NATO carries out joint air policing efforts in the region.
The two Typhoon jets intercepted "a Russian military Tu-134 passenger jet, known by the NATO name Crusty, that was being escorted by two Sukhoi Su-27 Flanker fighter jets, and an AN-12 Cub military transport aircraft," the RAF said.
The news comes amid renewed public appeals by Ukrainian leaders for western fighter jets. They say the jets are needed urgently to defend against Russian missiles and drone attacks.
But NATO allies are unlikely to send more advanced jets to Ukraine, defense experts have told CNN.
An interception of this kind is not atypical for NATO aircraft, but the joint air policing mission is a first for two NATO allies, the statement said.
The RAF described the operation as reassurance that the UK, Germany and other NATO countries "stand with their Estonian ally at this time of tension."
"We quickly identified the Russian aircraft and then monitored it as it flew close to NATO airspace," Richard Leask, an RAF commander, said in the statement.
Air policing missions help NATO identify any aircraft of interest, "ensure we know who they are" and keep everyone in the airspace safe, Leask continued.
"This is part of being a fighter pilot and is what we and our German colleagues have trained together to be able to do," the commander said.
The RAF is deployed in Estonia on Operation Azotize, which is tasked with defending against any aircraft that causes concern in Baltic airspace, the military statement said.
The UK will take over leadership from the German detachment in April and joint missions between the allies will continue to be flown until the end of that month.
The two intercepts involving NATO aircraft this week come after the release of stunning aerial video showing a Russian jet buzzing and then apparently hitting a US drone over the Black Sea.
The drone's downing highlighted the risk of a direct clash between Russian and NATO assets during Moscow's ongoing war in Ukraine.