Estonia summoned a Russian diplomat to protest after three Russian fighter aircraft entered its airspace without permission Friday and stayed there for 12 minutes, the Foreign Ministry said.

It happened just over a week after NATO planes downed Russian drones over Poland and heightened fears that the war in Ukraine could spill over.

Foreign Minister Margus Tsahkna said Russia violated Estonian airspace four times this year “but today’s incursion, involving three fighter aircraft entering our airspace, is unprecedentedly brazen.”

Estonian Defense Minister Hanno Pevkur also said the government had decided “to start consultations among the allies” under NATO’s article 4, he wrote on X, after Russian jets “violated our airspace yet again.”

The North Atlantic Council, NATO’s principal political decision-making body, is due to convene early next week to discuss the incident in more detail, NATO spokesperson Allison Hart said Friday.

Article 4, the shortest of the NATO treaty’s 14 articles, states that: “The Parties will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the Parties is threatened.”

U.S. President Donald Trump told reporters he will soon be briefed by aides on the reported incursion. “I don’t love it,” he said, adding, “I don’t like when that happens. It could be big trouble, but I’ll let you know later.”

Russia’s violation of Poland’s airspace was the most serious cross-border incident into a NATO member country since the war in Ukraine began with Russia’s all-out invasion in February 2022. Other alliance countries have reported similar incursions and drone crashes on their territory.

The developments have increasingly rattled European governments as U.S.-led efforts to stop the war in Ukraine have come to nothing.

The European Union’s foreign policy chief Kaja Kallas called Friday’s incursion “an extremely dangerous provocation” that “further escalates tensions in the region.”

“On our side, we see that we must show no weakness because weakness is something that invites Russia to do more,” she said. “They are increasingly more dangerous — not only to Ukraine, but also to all the countries around Russia.”

Estonia, along with fellow Baltic states Lithuania and Latvia and neighboring Poland, are staunch supporters of Ukraine.

The Russian MIG-31 fighters entered Estonian airspace in the area of Vaindloo Island, a small island located in the Gulf of Finland in the Baltic Sea, the Estonian military said in a separate statement.

The aircraft did not have flight plans and their transponders were turned off, the statement said, nor were the aircraft in two-way radio communication with Estonian air traffic services.

Italian Air Force F-35 fighter jets, currently deployed as part of the NATO Baltic Air Policing Mission, responded to the incident, according to the

statement.