Trump has said construction of the ballroom will be funded by private donors. But Senate Republicans are seeking $1bn in taxpayer funding to the Secret Service for security upgrades, including the ballroom, even though the bulk of the legislation is devoted to immigration enforcement.

Trump’s congressional allies are invoking complex budget rules to secure passage without any Democratic support. Democrats have opposed funding for Trump’s signature immigration crackdown absent reforms they have sought since federal immigration agents killed US citizens in separate incidents in Minnesota in January.