Sen. Ted Cruz, R-Texas, on Thursday blasted Twitter for blocking tweets that include the term “illegal alien,” The Hill reports.

Twitter rejected paid promotion for a tweet from the Center for Immigration Studies that included the phrase “illegal alien,” according to the think tank’s executive director, Mark Krikorian.

“Twitter just rejected paid promotion of the tweet below, saying: ‘This determination is based on the following Twitter Ads policy: Hateful Content,’” Krikorian tweeted on Wednesday. “It's because it contains the phrase ‘illegal alien’, which @TwitterAdsHelp deems unacceptable.”

“Does Twitter now ban the plain text of federal law?” Cruz asked in a tweet on Thursday. “8 U.S. Code § 1252c is entitled ‘Authorizing State and local law enforcement officials to arrest and detain certain illegal aliens.’ It authorizes the state or local arrest of illegal alien felons.”

Twitter has denied that its policies on paid promotion ban the use of the phrase “illegal alien,” and said that the action was based on the general content of the think tank’s tweets, but said that the decision was a mistake and has since been reversed.