A 17-year-old boy from McKinney, Texas, has been arrested on suspicion of planning to assassinate a Republican congressman and carry out an attack in the name of ISIS.
Representative Keith Self, who is a staunch supporter of President Donald Trump and has called for confronting the spread of radical Islam in the US, was claimed to be the intended target of the assassination.
Dallas media outlet WFAA reported, quoting law enforcement sources, that the suspect was arrested on October 5 after acquiring a firearm and that the boy had been recently radicalised.
Mr Self thanked the FBI and law enforcement.
"Preserving our constitutional republic from radical Islam means accepting the costs that come with it – name-calling, threats and worse," he said in a post on X on Wednesday. "This only strengthens my resolve. I will not back down."
The suspect's name has not been released. It is unclear how he came to the attention of law enforcement and for how long he had been monitored. The FBI declined to comment.
Mr Self has been at the forefront of a Republican effort to oppose the perceived incursion of radical Islam in the US. He, along with fellow Texas representative Chip Roy, launched the Sharia-Free America Caucus this year.
“If we do not fight back, Sharia will dominate our culture and America will no longer be America,” Mr Self said at the time.
Critics say the intensified scrutiny of the Muslim community by him and others is Islamophobic and part of a tactic to stir up the Republican base before major elections.
There has been a rise in political violence in the US since Mr Trump returned to office last year. He has been a target of at least two earlier assassination attempts.
The Democratic Speaker of the Minnesota House of Representatives, Melissa Hortman, and her husband Mark were killed last year.