President Donald Trump expanded his attacks on major U.S. law firms on Tuesday as he signed an executive order targeting Jenner & Block, which represents clients challenging some of his major policies and formerly employed a prosecutor involved in a special counsel investigation of his 2016 campaign.

Jenner & Block and WilmerHale are seeking summary judgments against what one of them called “a plain violation of the First Amendment.”

A judge overstepped his authority in halting much of an order targeting Jenner & Block, as US agencies retain the power to decide who to work with, Trump administration officials said Tuesday.