The Patriot, short for Phased Array Tracking Radar for Intercept on Target, is a mobile surface-to-air missile defence system developed by Raytheon Technologies. It is considered one of the most advanced air defence systems in the U.S. arsenal and has been in service since the 1980s.

Latest news and live updates as Trump announces the U.S. will send Patriot missiles to Ukraine and meets with NATO's secretary general.

Trump's moves underline his growing disenchantment with Russian President Vladimir Putin over the lack of progress in U.S.-led efforts to secure a ceasefire.