George Russell says a number of Formula One drivers are "probably a bit fed up" of governing body FIA.

The Grand Prix Drivers' Association (GPDA), which Russell is the director for, put out a statement after the last race in Brazil to raise concerns about multiple issues.

The GDPA asked president Mohammed Ben Sulayem to "consider his own tone and language", having previously punished Max Verstappen for using bad language at a press conference.

Speaking ahead of this weekend's Las Vegas Grand Prix, Russell confirmed the FIA had yet to respond to the letter as he expressed further disappointment.

"We recognise everybody's working as hard as they can to do the best job possible," Russell told reporters. "There is obviously a huge amount of change within the FIA quite regularly, so it's clearly not the most stable of places.

"And maybe that's why it's been a bit challenging to get some of the changes that we've wanted implemented. Of course, everyone has their own side to their own story.

"I think if we feel that we're being listened to and some of the changes that we are experiencing, requesting, are implemented, because ultimately we're only doing it for the benefit of the sport, then maybe our confidence will increase.

"But, I think there's a number of drivers who feel probably a bit fed up with the whole situation. And it only seems to be going in, to a degree, the wrong direction."

Russell also said he and his fellow drivers were not aware of race director Niels Wittich being removed three races before the season ends.

"Talking as a fellow driver as opposed to my role with the GPDA, everybody felt with certain things that have happened that we wanted to stand united," he said.

"At the end of the day, we just want to be transparent with the FIA and have this dialogue. And the departure of Niels is a prime example of not being part of these conversations. [The letter] is kind of us putting the pressure back on them."