The UK is deploying a ground based air defence system to Poland along with 100 troops.
Defence Secretary Ben Wallace announced the deployment of the Sky Sabre missile system while on a trip to Warsaw to meet his Polish counterpart on Thursday.
The deployment will help shore up NATO’s eastern flank bordering Russia in a defensive measure as Moscow entered its fourth week of the invasion into Ukraine.
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NATO countries – including the UK and Poland – are sending a clear message of unity to Russia.
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Boris Johnson’s spokesman said: “We want to ensure the borders of Europe are well-protected.”
The air defence system has a greater range than its predecessor and can take out fighter jets or target incoming smart bombs.
“We are going to deploy the Sky Sabre medium-range anti-air missile system to Poland with about 100 personnel to make sure that we stand alongside Poland, protecting her airspace from any further aggression by Russia,” Mr Wallace said.
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It supersedes the ageing Rapier Short Range Air Defence system used by the British Army.
The 100 troops will be deployed on a short-term basis and will be kept under review, Downing Street said.
A spokesman added that the missile system “will remain under UK control at all times”.
On Sunday, Russian missiles attacked a Ukrainian military training base just 15 miles from the Polish border, killing 35 people.
Mr Wallace’s arrival in Poland follows a meeting of NATO foreign ministers in Brussels yesterday where the defence secretary said it was a “privilege” to be part of the “self-defencing” alliance.
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Britain has sent shoulder-fired short-range anti-tank weapons to Ukraine, credited with helping stall the advance of Russian armoured columns.
Earlier this week, the government also ramped up action against Russia, imposing further sanctions on hundreds more oligarchs.
It also banned British exports to Russia of luxury goods and imposed a 35 percentage point tariff hike on key Russian imports such as vodka, cereals and metals.