Sebastian Vettel didn't outright dismiss reports linking him with moves to Mercedes and McLaren, but insists "nothing has changed" regarding his future.
The four-time World Champion's current Red Bull contract runs until the end of the 2015 season, but he has in recent days been rumoured to be the targets of both Merc and McLaren.
According to Red Bull's motorsport advisor Dr Helmut Marko, Mercedes are looking to have an all-German team in Vettel and Nico Rosberg from 2016 while McLaren have also made a big-money offer.
Rosberg has signed a new deal with his Brackley-based squad in recent weeks while Lewis Hamilton's deal with Merc is due to run out at the end of 2015.
Although Hamilton has indicated he wants to stay and claimed he is "not worried" about the Vettel speculation, Mercedes' motorsport chief Toto Wolff refused to put out the flames.
"We are talking about a handful of top drivers. All the best teams fight over them," Wolff said. "We try to build a picture of how the market moves until we come to our decisions."
Vettel, meanwhile, admits he would have to look at any offer.
"I think any offer has to be considered but nothing has changed," the German said. "I still don't talk about these things.
"I don't know which sources Helmut has, or doesn't have, but they seem to vary, let's say."