Britain’s foreign secretary Yvette Cooper on Monday warned that Russia’s incursions into NATO territory risked sparking an armed conflict, drawing an immediate rebuke from Moscow, which dismissed Europe’s concerns as groundless and hysterical.

At a United Nations Security Council meeting, Cooper confronted Russia: "Your reckless actions risk direct armed confrontation between NATO and Russia. Our alliance is defensive but under no illusion we stand ready to defend NATO's skies and NATO's territory."

"If we need to confront planes operating in NATO space without permission then we will do so," she added.

The United States also reinforced its commitment to NATO. Michael Waltz, the new US envoy to the UN, said: "I want to take this first opportunity to repeat and to emphasize that the United States and our allies will defend every inch of NATO territory."

Cooper’s stance was echoed by other Western ministers, who said the repeated incidents could not be considered accidental.

The warning followed Estonia’s report that three Russian MiG-31 fighter jets entered its airspace on Friday, staying for 12 minutes before being forced out. Just a week earlier, more than 20 Russian drones had crossed into Polish airspace, prompting NATO jets to shoot some of them down.

The Security Council convened on Monday to address the issue. NATO consultations were scheduled for Tuesday.

Russia’s deputy ambassador to the UN, Dmytry Polyanskiy, dismissed the claims: "We won't be partaking in this theater of the absurd. When you decide that you want to engage in a serious discussion about European security, about the fate of our common continent, about how to make this continent prosperous and secure for everybody, we'll be ready."