Speaker of the House Rep. Nancy Pelosi (D-Calif.) and Senate Minority Leader Sen. Chuck Schumer (D-N.Y.) put out a statement on Thursday asking that Special Counsel Robert Mueller testify before both houses of Congress "as soon as possible."
Mueller was investigating the possibility of collusion between the Trump campaign and Russia.
A four-page summary provided by Attorney General William Barr stated that "[t]he investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."
Pelosi and Schumer accused Barr of trying to cover for the president.
The White House is preparing its own response to the Mueller report, which will reportedly defend against accusations of obstruction that it expects to be levied against President Donald Trump.