U.S. President Donald Trump said Monday the United States will send additional weapons to Ukraine, after Russia claimed new gains in its grinding war against its neighbor.

Trump's announcement followed Washington saying last week that it was halting some weapons shipments to Kyiv, leaving Ukrainian officials caught off guard and scrambling for clarity.

A pause poses a potentially serious challenge for Kyiv, which is contending with some of Russia's largest missile and drone attacks of the more than 3-year-old war.