Russia's Defence Ministry denied its jets violated Estonian airspace, saying they flew over neutral waters.

With tensions already high because of the war in Ukraine, the incursion came just over a week after more than 20 Russian drones entered Polish airspace on the night of Sept. 9-10. That prompted NATO jets to down some of them and Western officials to say Russia was testing the alliance's readiness and resolve.

It also occurred three days after Russia and Belarus ended their "Zapad-2025" joint military exercises, which included the rehearsal of the launch of Russian nuclear weapons.

Tallinn said the three MiG-31 fighter jets entered Estonian airspace without permission and stayed for a total of 12 minutes before they were forced to withdraw, during which time the high-speed aircraft could have traversed broad swaths of the country.

"Russia has violated Estonian airspace four times already this year, which is unacceptable in itself, but today's violation, during which three fighter jets entered our airspace, is unprecedentedly brazen," Foreign Minister Margus Tsahkna said.

Russian jets routinely fly over the Baltic Sea between mainland Russia and its exclave of Kaliningrad.

In a statement issued early on Saturday, the Russian Defence Ministry said its jets flew over neutral waters of the Baltic Sea in proceeding from northwest Russia to Kaliningrad.

"The flight was carried out in strict conformity with international rules governing airspace with no violation of the borders of other states as is confirmed by independent checks," the ministry said of the three MiG-31 fighters in a post on Telegram.

"During the flight, the Russian aircraft did not deviate from the agreed flight path and did not violate Estonian airspace."

Separately, Poland said on Friday two Russian fighter jets violated the safety zone of the Petrobaltic drilling platform in the Baltic Sea.

Eyes on Trump

United States President Donald Trump said late on Friday afternoon he had not been briefed on the incident but expected he would be later.

"I don't love it. I don't like when that happens," Trump told reporters when asked if he saw the incursion by Russian jets as a threat to NATO. "Could be big trouble. I'll let you know later."

Trump's administration is being closely watched for a response.

Washington had little to say about the drone incursion into Poland and did not participate directly in fending it off, triggering anxiety among NATO members, who have questioned Trump's commitment to their defence in case of a Russian attack.

NATO said Russia was reckless.

"Earlier today, Russian jets violated Estonian airspace. NATO responded immediately and intercepted the Russian aircraft. This is yet another example of reckless Russian behaviour and NATO's ability to respond," a NATO spokesperson said on X.

'No accident'

Europeans quickly responded to the Russian jet incident on Friday. "This was no accident," EU foreign policy chief Kaja Kallas, a former Estonian prime minister, said in comments relayed by a spokesperson.

Estonia said it had summoned the top Russian diplomat in the country to lodge a protest and deliver a note.

Estonian Prime Minister Kristen Michal said his country had decided to ask NATO to open consultations under Article 4 of the alliance's treaty, and that the Russian jets flew around 5 nautical miles (9 kilometers) into NATO airspace before Italian F-35s, currently stationed at a base in Estonia, pushed them out.

NATO polices the airspace of Estonia and other Baltic nations in its "Baltic Sentry" mission.

Tsahkna suggested that Estonia would be asking allies for more air defences. "It was a very clear provocation. It was definitely meant like this. And that's why we are calling the Article 4 political consultations," he told Reuters.

Article 4 states that members of the North Atlantic Treaty Organization will consult together whenever, in the opinion of any of them, the territory, political independence or security of any of them is threatened.

Ukraine called the incursion an unacceptable new destabilisation measure by Russia and said it stands with Estonia. "Strong action is needed, both jointly and from individual countries," President Volodymyr Zelenskiy said on the Telegram messaging app.

Lithuanian Defense Minister Dovile Sakaliene said NATO should urgently move air defence capabilities to frontline states.

"We are being tested, our citizens are being threatened almost every day now. This means that we need to have capabilities collected from our allies (to be placed) by our borders, because that's the border of NATO," she told Reuters.