U.S. President Donald Trump on Thursday signed an executive order suspending security clearances for employees of law firm Perkins Coie and targeting the firm's business with federal contractors, citing its diversity practices and political activities.

Trump says he's suspending security clearances of lawyers at Perkins Coie, which was involved in launching oppo research during the 2016 campaign into any ties between Trump and Russia.

The order against the firm, which did work for Democrats during the 2016 campaign, represents an escalation of efforts to punish groups the president sees as aiding his enemies.