Estonia is calling on its Western allies to show unity in the face of growing aggression, the Baltic nation’s foreign minister said Friday after three Russian fighter jets entered its airspace.

Speaking in an interview with POLITICO, Estonian Foreign Minister Margus Tsahkna said that the incursion showed Russian leader Vladimir Putin has no interest in peace.

“This was a heavy violation by Russia — three fighters, MiG-31s, entered NATO airspace for 12 minutes,” he said. “NATO acted very adequately and by the book. But if you see what Russia is doing, they are putting more pressure on NATO.”

Earlier Friday, Estonian officials confirmed to POLITICO that three warplanes had crossed into Estonian airspace and were forced out after Italian jets were scrambled to deal with what the EU’s top diplomat, Kaja Kallas, described as an “extremely serious provocation.”

“We need to understand that Putin doesn’t want to have any kind of peace in Ukraine,” Tsahkna said. “Instead, Putin is bombing Ukraine, killing people in the middle of the day … also more actively against NATO.”

Estonia, the top diplomat confirmed, has triggered Article 4 of NATO’s treaties, which calls for urgent discussions with allies.

“Russia is testing NATO, the unity of Europe,” he said. “The Eastern flank is taking more responsibilities. We are the first line … Article 4, we call it now and we need to have a conversation about what can we do more.”

The incident is the third such breach of NATO airspace in a matter of days — with Russian drones crossing over into Poland and Romania.

Announcing a new round of EU sanctions on Russian energy and financial transactions on Friday, European Commission President Ursula von der Leyen said that “again and again, President Putin has escalated and in response, Europe is increasing its pressure,” she said.

“We know that our sanctions are an effective tool of economic pressure, and we will keep using them until Russia comes to the negotiating table.”

The EU has been working to convince U.S. President Donald Trump to take a tougher line against the Kremlin, which has so far resisted his efforts to begin diplomatic talks to end its war in Ukraine.

Brussels has dispatched a team of experts to Washington to help develop secondary sanctions, while the White House has pledged tougher restrictions if and when NATO allies fully quit Russian oil.