President Donald Trump sought to ramp up investigations of unnamed groups his administration suspects of supporting political violence, signing a presidential memorandum that critics worry will be used to target his political enemies, writes CNN.

The directive aims to intensify efforts across the government to identify organizations backing what officials called "domestic terrorism and organized political violence being perpetrated by radical, politically motivated groups" in the wake of the killing of conservative activist Charlie Kirk earlier this month.

"We`re going to get out there and we`re going to do a pretty big number on those people", Trump said from the Oval Office, claiming without evidence there are "wealthy people" funding political violence.

The memorandum comes as Trump has blamed the "radical left" for Kirk`s killing and other recent violent incidents, including a fatal shooting on Wednesday at an ICE facility in Dallas despite limited public information about the motive. The White House previously designated Antifa as a domestic terrorist organization, despite the fact that it lacks a centralized organizational structure or defined leadership.

Asked what other groups the administration might target under Thursday`s memo, Trump and other officials would not identify any specific organizations.