"Earlier today, Russian jets violated Estonian airspace," alliance spokesperson Allison Hart posted on X.

"NATO responded immediately and intercepted the Russian aircraft," she wrote. "This is yet another example of reckless Russian behaviour and NATO's ability to respond."

Tallinn said the three Russian MiG-31 fighter jets had entered its airspace over the Gulf of Finland, remaining for 12 minutes.

A NATO official said they were met by Italian F-35 aircraft, deployed as part of an alliance mission in the Baltic region.

"Europe stands with Estonia in the face of Russia's latest violation of our airspace," European Commission president Ursula von der Leyen wrote on X.

"As threats escalate, so too will our pressure," said the EU chief, who Friday put forward a 19th package of sanctions targeting Moscow over the Ukraine war for approval by the bloc's member states.

The EU's top diplomat Kaja Kallas -- formerly Estonia's prime minister -- condemned the third violation of EU airspace in under two weeks as an "extremely dangerous provocation" by Moscow.

After incidents over Poland and Romania, the latest violation "further escalates tensions in the region," she said, vowing the European Union would "continue to support our member states in strengthening their defences."

"Putin is testing the West's resolve," Kallas said. "We must not show weakness."