A dispute over a plan to re-draw electoral boundaries in the US state of Texas has escalated again after a senator said the Federal Bureau of Investigation (FBI) had agreed to help find Democrats who have fled the state.

The FBI would not confirm whether they agreed to help and the senator, Republican John Cornyn of Texas, did not specify what kind of assistance the FBI would offer.

It comes a day after some Democrats were forced to evacuate a hotel where they were staying in Illinois, as they protest Republicans' efforts to change the map of congressional districts

Earlier this week, US President Donald Trump said the FBI "may" have to get involved.

Sen Cornyn said in a statement that FBI Director Kash Patel had "approved my request for the FBI to assist state and local law enforcement in locating runaway Texas House Democrats".