Sen. Ted Cruz is asking the FBI to investigate antifa, a militant left-wing group known to assault political opponents and journalists.

The Texas Republican informed FBI Director Christopher Wray during a hearing Tuesday he would be sending a letter to the bureau and Justice Department officially asking for a Racketeer Influenced and Corrupt Organizations Act investigation, which is designed to target organized crime in the U.S.

"The bureau has significant tools to go after organizations, criminal enterprises that engage, that use anonymity, that use masks to carry out violence, groups like the Klan, groups like at times the Mafia," Cruz said, noting that he believes antifa has engaged in a similar coordinated effort.

Wray said the FBI views antifa as more of an ideology and noted the bureau does not investigate ideology. But he stressed that the FBI takes violence on behalf of any ideology seriously and has a number of smaller scale inquiries underway.

"We have a quite a number though, I should tell you, of properly predicated investigations of what we categorize as anarchist extremists. People who are trying to commit violent criminal activity that violates federal criminal law and some of those people do subscribe as what we would refer to as a kinda of a antifa-like ideology," he said.

Wray said he would read Cruz's letter, which the senator later shared on Twitter.

Today I penned a letter to Attorney General William Barr, Deputy Attorney General Jeffrey Rosen, and FBI Director Christopher Wray calling for an investigation into Antifa under the Racketeer Influenced and Corrupt Organizations Act (RICO). pic.twitter.com/ptY0syxPrn — Senator Ted Cruz (@SenTedCruz) July 23, 2019

The hearing took place days after Cruz and fellow Republican Sen. Bill Cassidy of Louisiana filed a resolution Thursday to categorize antifa as a domestic terrorist organization.

The resolution says the group diametrically opposes First Amendment values of peaceful assembly and free speech. It also cites the physical assault of journalist Andy Ngo in Portland, Oregon, in late June and the threats antifa members have issued toward employees of U.S. Immigration and Customs Enforcement.

The resolution also calls on the federal government to deploy "all available and appropriate tools" to combat the spread and growth of domestic terrorism in the U.S., grouping antifa in with white supremacist terrorism.

Cruz told Wray that his letter to the DOJ and the FBI will also "focus on some local elected officials who have chosen to deny police protection to their citizens based on political ideology. That is a pattern that we have seen with politicians who favored Klan violence and I think every citizen deserves law enforcement protection regardless of their political ideology."

This appears to target Portland Mayor Ted Wheeler, a Democrat, whom Cruz accused of ordering his police officers to let citizens be attacked by "domestic terrorists" after the assault on Ngo left him badly injured and demanded legal action.

Wheeler denied the accusation in a tweet. "At least get your facts straight. I ordered no such thing," he said to Cruz. "Could you divert some of those investigation dollars to something that would actually benefit American cities? Infrastructure, affordable housing, mental health services come to mind."