Robert Blair, senior advisor to acting chief of staff Mick Mulvaney, will not appear before House impeachment inquiry committees under a White House directive, the Financial Times first reported Saturday night.

What they're saying: Blair's attorney Whit Ellerman said in a statement to news outlets including the FT and CNN, "Blair is caught between the assertions of legal duty by two coequal branches of government, a conflict which he cannot resolve."

"In light of the clear direction he has been given by the executive branch, Mr. Blair has respectfully declined to appear and testify. Nevertheless, he will fulfill all his legal duties once that conflict is appropriately resolved."

The big picture: Blair was requested to appear on Friday before three House committees investigating President Trump and Ukraine.

He has yet to receive a subpoena, but Ellerman told CNN the "direction from the White House" and advice from the Justice Department "on which it is based, covers subpoenas."

Go deeper: The coming appearances in House Democrats' impeachment probe