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Britain is to send to Ukraine armoured vehicles that can fire missiles against invading Russian aircraft, UK Defence Secretary Ben Wallace said on Monday.
"We shall be gifting a small number of armoured vehicles fitted with launchers for those anti-air missiles," he said.
"These Stormer vehicles will give Ukraine forces enhanced short-range anti-air capabilities both day and night."
Mr Wallace said Britain's assessment was that about "15,000 Russian personnel have been killed during their offensive. Over 2,000 armoured vehicles have been destroyed or captured".
More than a quarter of the 120 battalion tactical groups Russia had committed to invading Ukraine "have been rendered not combat-effective", he said.
Mr Wallace said Britain's military contribution so far included 5,000 anti-tank missiles, five air defence systems with more than 100 missiles, and 4.5 tonnes of plastic explosives.
Prime Minister Boris Johnson recently said Britain would send 120 armoured vehicles to Ukraine, as well as anti-ship missiles.
US Defence Secretary Lloyd Austin said on Monday that Ukraine could win the war against Russia if it had the "right equipment".
The conflict has brought an outpouring of support from western nations with many weapons sent to Ukraine to help beat back the Russian invaders.