It's unclear what role federal agents can play in the matter, and there were no reports of FBI activity in the area housing Texas Democrats as of Thursday morning.

Texas Republican U.S. Sen. John Cornyn said Thursday the FBI has granted his request to assist Texas law enforcement in locating House Democrats who fled the state, setting up a potential confrontation with Illinois Democratic officials who have vowed to protect them.

"They're grandstanding," Pritzker said, brushing off President Trump's threats. "There literally is no federal law applicable to this situation."