MotoGP riders have cast doubt over whether next year's proposed Mexico race will take place, as concerns over the track's safety mount.
It emerged in Brno last weekend that the Mexico City circuit is a serious contender for a 2019 calendar slot, and could be handed an April date to run back-to-back with the Austin round.
But Valentino Rossi described the circuit, which hosts Formula 1 and features many walls in close proximity to the track, as being too "dangerous" for MotoGP.
Other riders were asked about the venue ahead of this weekend's Austria race, with Marc Marquez saying riders were promised in the most recent safety commission meeting that changes would be made to run-off areas before any race took place in Mexico.
Ducati's Andrea Dovizioso said he doubts necessary improvements could be made in time.
"We spoke about it in the last safety commission, we will speak again during this weekend," said Dovizioso. "But I don't think everything is fixed.
"We gave our opinion, but like Marc [Marquez] said, we can't really see on the paper [how effective changes will be]. So if that has to happen, we have to have a test and have to understand the situation better.
"I don't know the details, but I don't think at the moment we are going to Mexico."
Aleix Espargaro agreed that a test would be necessary to assess the circuit's safety, but did not think there was enough time for that to happen before a 2019 race.
"The right way to do things is as we did in Thailand - we test, see everything, do a safety commission [meeting], approve [it] and then we go," he said.
"I don't want to speak bad about the track or the decision they made, because I've never been there, I've never seen anything.
"They say we race on tracks that are a lot [more] dangerous. Motegi, for example. And if we agree to go to Motegi, they say it's safer to go there.
"What I don't like is to go somewhere without trying. For me, before we go there [to race] we have to go there and test. But there is no time because the race will be in six months."
LCR Honda's Cal Crutchlow was more enthusiastic about a possible Mexico visit, but admitted he was also unsure about whether the race will go ahead.
"There was a discussion to go there, I'm happy to go," said Crutchlow. "If they make the changes they say they're gonna make, why not?
"It's another place that we will be able to perform, I think we'll have a fantastic crowd. If the track is safe enough I think you'll see a great race again.
"I honestly don't know if we're going or not. It got proposed to us, we all sat down as riders and discussed it, the outcome is not our outcome at the moment.
"We have to leave it with them and see what the decision is."