President Donald Trump warned Republicans on Wednesday that failure to pass his massive tax and immigration package would be “ultimate betrayal.” In a statement, the White House said the bill needs to “pass immediately” to keep promises that Trump and fellow Republicans made while campaigning.

But the tax cut package that passed the U.S. House and President Trump has dubbed the "big, beautiful bill" may change before it becomes law.

U.S. Senate Republicans said on Thursday they will seek substantial changes to President Donald Trump's sweeping tax and spending bill after it narrowly won approval in the House of Representatives, in a sign that significant hurdles remain for the package.