More: Senate Appropriations Chair Susan Collins, R-Maine, said the White House budget office "intentionally withheld these funds for months to execute this unlawful cancellation of appropriations that were approved on a bipartisan basis and signed into law."

"I will work with my colleagues to address these illegal actions," she added in a statement.

And Connecticut Rep. Rosa DeLauro, the House Appropriations Committee's ranking Democrat, echoed that view.

"Not only is freezing the money in this proposal illegal, but the administration has also clearly been unlawfully impounding funds all year just to get to this point," DeLauro said in a statement.