US Attorney General Pam Bondi ordered federal law enforcement to step up investigations into the anti-fascist antifa movement and similar "extremist groups" and asked the FBI to compile a list of entities possibly engaged in domestic terrorism, according to an internal memo.

The memo, sent to prosecutors and federal law enforcement agencies, calls on the Justice Department to prioritise investigating and prosecuting acts of domestic terrorism, including any potential "tax crimes" involving "extremist groups" who defrauded the Internal Revenue Service.

It comes several months after President Donald Trump signed an order targeting antifa as a terrorist organisation and pledged to go after left-wing groups following the assassination of Charlie Kirk.

Antifa, short for anti-fascist, is a "decentralised, leaderless movement composed of loose collections of groups, networks and individuals," according to the Anti-Defamation League, which tracks extremists.

"These domestic terrorists use violence or the threat of violence to advance political and social agendas, including opposition to law and immigration enforcement; extreme views in favour of mass migration and open borders; adherence to radical gender ideology, anti-Americanism, anti-capitalism, or anti-Christianity," Bondi wrote in the memo.

She wrote that the FBI's Joint Terrorism Task Forces "shall prioritise the investigation of such conduct".

She also ordered federal law enforcement agencies to scour their files for any intelligence they might have on antifa groups and provide it to investigators.

The FBI and joint terrorism task forces will also be asked to investigate incidents over the past five years that may have involved acts of domestic terrorism, from the doxxing of law enforcement to the targeting of Supreme Court justices, according to the memo.

After the FBI compiles a list of possible groups engaged in alleged acts of domestic terrorism, the agency is required to develop new strategies similar to those used to counter violent and organised crime to "disrupt and dismantle entire networks of criminal activity."

Bondi also called on the department's grant-making offices to prioritise awarding funding to states and municipalities that have programmes designed to protect against domestic terrorism and instructs the FBI to update and improve its tip line so that "witnesses and citizen journalists can send media of suspected acts of domestic terrorism". (Reuters)