NATO responded immediately and intercepted the Russian jets which violated Estonian airspace, calling the violation "reckless", a NATO spokesperson has said in a statement.
"This is yet another example of reckless Russian behaviour and NATO's ability to respond," the spokesperson said.
Earlier, NATO member Estonia's airspace was violated by three Russian military jets, its government said, amid an increasingly tense atmosphere on the alliance's eastern flank.
The incident comes just over a week after more than 20 Russian drones entered Polish airspace on the night of 9-10 September, prompting NATO jets to down some of them and Western officials to say Russia was testing the alliance's readiness and resolve.
Tallinn said today the three MiG-31 fighter jets entered Estonian airspace without permission and stayed there for a total of 12 minutes.
"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," said Foreign Minister MargusTsahkna.
"Russia's ever-increasing testing of borders and aggressiveness must be responded to by rapidly strengthening political and economic pressure."
Estonia said it had made a protest to the top Russian diplomat in the country.
A staunch supporter of Ukraine, Tallinn said in May that Moscow had briefly sent a fighter jet into NATO airspace over the Baltic Sea during an attempt to stop a Russian-bound oil tanker thought to be part of a "shadow fleet" defying Western sanctions on Moscow.
The EU's foreign policy chief Kaja Kallas called the violation of Estonian airspace an "extremely dangerous provocation".
Today's violation of Estonia's airspace by Russian military aircraft is an extremely dangerous provocation.
— Kaja Kallas (@kajakallas) September 19, 2025
This marks the third such violation of EU airspace in days and further escalates tensions in the region.
The EU stands in full solidarity with Estonia (1/2)
"This marks the third such violation of EU airspace in days and further escalates tensions in the region," Ms Kallas said in a post on X.
"We will continue to support our member states in strengthening their defences with European resources.
"Putin is testing the West's resolve. We must not show weakness."
Estonian Defence Forces said the airspace violation occurred this morning in the area of Vaindloo Island, around 100km from the capital Tallinn.
The aircraft did not have flight plans, their transponders were not switched on and they were not in contact with air traffic control, Estonia said.
While incursions over Vaindloo Island by Russian aircraft are fairly common, they do not usually last as long as Friday's incident.
"It's tough to see how this wasn't intentional," a US official, speaking on the condition of anonymity, said.
The official noted that it was difficult to see a situation where that many Russian aircraft did not know they were in Estonian airspace for that long, but added that a deeper assessment was ongoing.
Ukraine courts foreign cash for military 'Silicon Valley'
At the opening of Ukraine's biggest defence tech fair, arms executives and government officials were welcomed by a giant movie screen blaring an action-style trailer with heavy base undertones.
The two-day event is part of Ukraine's bid to position itself as a leader in military innovation and encourage hesitant foreign investment, more than three and a half years into the Russian invasion.
"We need to forget Silicon Valley - it's the past. Ukraine is the future," Europe's Commissioner for Defence Andrius Kubilius said at the event, which began on Tuesday and the details of which were only made public today.
The idea that Ukraine's Western allies could learn from Kyiv has taken on new weight after more than a dozen Russian drones flew through Poland's airspace last week.
Moscow has denied targeting the NATO member, but for some, the incident exposed the alliance's weaknesses.
Seen from Kyiv, the scrambling of jets and firing of advanced missiles to try to down the drones was an outdated - and far too expensive - response.
"We understood a very simple truth: that we do not have those capabilities which Ukraine has, to fight against drone invasion," Mr Kubilius said.
Buzzing robots
To counter nightly Russian drone attacks, Ukraine has developed a suite of cheap and effective tools, like electronic jammers and interceptor drones.
It has been downing more than 80% of the thousands of Russian drones that are fired at it every month, AFP analysis of Kyiv's air force data shows.
On the other hand, the scrambled NATO forces shot down under five of the 20-odd that flew through Poland last week.
Kyiv's strategy has been to repurpose basic consumer tech for military purposes - such as strapping explosives to small first-person-view drones that are used to film aerial landscapes or stunts.
Their unmistakable buzz filled the exhibition zone at the Lviv fair.
Futuristic robots resembling oversized remote-controlled cars - designed to ferry weapons to the front or evacuate wounded soldiers from the battlefield - were also on display.
Adding to the Silicon Valley vibe, young engineers hovered over sleek screens showing how they could be integrated with artificial intelligence.
"This is a display to show that Ukraine is tech-savvy and growing. That you need to be in Ukraine if you're in defence tech," said Thomas Moreau from the French defence trade association GICAT.
