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.

The firm will provide $40M in pro bono legal services to support Trump’s agenda after the president threatened to rescind some government contracts.

Brad Karp, the managing partner of the elite New York law firm, sent an email to its lawyers defending a highly criticized arrangement reached with the Trump administration last week.