(CNN) President Donald Trump Friday morning tweeted about the "costly" Russia investigations, the latest in a string of conservative complaints about the Russia probe led by special counsel Robert Mueller.

But Congress actually has little recourse to fight the budget for the special counsel.

The budget for Mueller's probe, which is investigating possible collusion between Trump associates and Russian officials and obstruction of justice, is not part of the annual funding for the Justice Department that Congress approves.

Instead, it comes out of a separate revolving Treasury Department account for "permanent, indefinite appropriations" and it is set up for things like special investigations. The special counsel has submitted his budget to the Justice Department for review.

A congressional appropriations aide said that the Justice Department is given financial discretion to appropriate funds for the special counsel probe, although the oversight committees do receive "accounting material related to this activity."

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