Ukraine needed this.After months of political wrangling and battlefield reversals, Kyiv has reason to cheer. Now the race is on to ensure that U.S. military aid gets to the front lines in time to make a difference to troops trying to ward off the advancing Russian army.

The Pentagon says the U.S. will provide Ukraine additional Patriot missiles for its air defense systems as part of a $6-billion additional aid package.

Much-needed munitions like artillery shells could start arriving relatively quickly, but experts say it could take weeks before U.S. assistance has a direct impact on the war.