The UK and other NATO allies are vowing to confront Russian planes and drones violating their airspace during a meeting at the United Nations, accusing the Kremlin of risking armed conflict.
It comes amid a growing pattern of Russian incursions in recent weeks, including three Russian fighter jets entering NATO airspace on Friday last week and drones falling into Polish territory on Wednesday.
A Russian military aircraft also entered neutral airspace over the Baltic Sea on Sunday, local time, prompting NATO planes to be flown out to escort it.
Confronting Russia at a meeting of the United Nations Security Council, British Foreign Secretary Yvette Cooper said: "Your reckless actions risk direct armed confrontation between NATO and Russia.
"Our alliance is defensive but be 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."
Estonia said on Friday that three Russian MiG-31 fighter jets had entered Estonian airspace without permission and stayed for a total of 12 minutes before they were forced to withdraw.
Western officials said the confrontation was designed to test NATO's readiness and resolve.
The incident occurred just over a week after more than 20 Russian drones entered Polish airspace, prompting NATO jets to shoot some of them down.
Ms Cooper's comments were echoed by other Western ministers in the Security Council, including EU foreign policy chief Kaja Kallas, who suggested the multiple incidents could not be considered an accident.
Russia labels UN meeting 'theatre of the absurd'
Ukraine's foreign minister Andrii Sybiha said such actions by Moscow should be met robustly and renewed an offer by Kyiv to integrate its air defences into those of neighbouring Western countries to counter the Russian front.
"A strong response means that a threat should not be escorted, neither for 12 minutes, nor for one minute. It should be neutralised," he said.
Making his first appearance since taking the post, the United States' new envoy to the UN Mike Waltz said Moscow needed to defuse tensions, not exacerbate them.
"I want to take this first opportunity to repeat and to emphasise the United States and our allies will defend every inch of NATO territory," Mr Waltz said.
Russia's deputy ambassador to the UN, Dmytry Polyanskiy, said there was no evidence backing their claims and accused European powers of levying baseless accusations.
"We won't be partaking in this theatre of the absurd," he said.
"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."
Reuters
