The Senate parliamentarian has advised a key Medicaid provider tax overhaul that's central to President Donald Trump's big tax cut and spending bill does not adhere to procedural rules.

The nonpartisan Senate official whose office determines if legislation fits within the rules of the chamber dealt Senate Republicans a blow on proposed changes to Medicaid.

Republicans in the U.S. Congress scrambled on Thursday to resolve nettlesome tax and health care provisions in their sweeping tax-cut and spending bill on Thursday as President Donald Trump pressed them to pass it by a July 4 deadline.