President Joe Biden said on Friday that the border deal being negotiated in the U.S. Senate was the "toughest and fairest" set of reforms possible and vowed to shut down the border the day he signs the bill. "What's been negotiated would – if passed into law – be the toughest and fairest set of reforms to secure the border we've ever had in our country," Biden said in a statement. Biden's comments come after bipartisan U.S. Senate talks on a border security deal that some have set as a condition for further Ukraine aid hit a critical point, lawmakers said on Thursday.