President Donald Trump said the US will send more Patriot air-defense batteries to Ukraine in an apparent shift to a more confrontational stance toward Russia after his attempts to negotiate a ceasefire failed.

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.