Qualifying for the Russian Grand Prix is in doubt after final practice was cancelled due to bad weather.
The session was due to start at 12pm local time (10am UK), but the running was cancelled following heavy rain in Sochi.
Formula One bosses remain hopeful that qualifying, scheduled for 3pm, will be able to go ahead.
However, plans are already in place to stage the action, which determines the grid, on Sunday morning if the rain persists.
FIA race director Michael Masi said: "What we've seen is that we will have this level of rain until about 1.30-2pm local time, and then it will decrease in the afternoon.
"The priority from today's perspective is obviously qualifying.
"But if qualifying is not able to happen today then we will hold it on Sunday."
Lewis Hamilton heads into the Russian GP five points adrift of championship rival Max Verstappen.
However, Verstappen is set to start from the back of the grid following a penalty for taking on his fourth engine – one more than is permitted for the season.