A deal to provide further U.S. assistance to Ukraine by year-end appears to be increasingly out of reach for President Joe Biden. The impasse is deepening in Congress despite dire warnings from the White House about the consequences of inaction as Republicans insist on pairing the funding with changes to America's immigration and border policies.

President Joe Biden called on congressional Republicans on Wednesday to put aside “petty, partisan, angry politics” and pass a multibillion-dollar aid package for Ukraine, warning that failure to do so could enable President Vladimir Putin of Russia to reclaim momentum in the war and even draw in American troops.

When President Biden sent his request to Congress last month for aid to Ukraine and Israel, he included a request for more money to help with security at the border with Mexico, a sweetener intended to both address a crisis and win over support of Republicans.