Multiple sources say an announcement, seen within the sport as just a matter of time, was expected by Monday at the latest with a March 20 deadline looming for freight that has to be transported to Bahrain for logistical reasons.
Sky Sports television, which has the broadcasting rights in Britain where most of the 11 teams are based, said it understood the races would be called off by Sunday night.
US and Israeli attacks on Iran are continuing while Iranian drones and missiles have hit some Middle Eastern capitals including Bahrain's Manama, where most team personnel would be staying in hotels.
Formula One is racing in China this weekend for the second round of the season after the opener in Australia last weekend.
Sources have indicated previously that neither Middle Eastern race is likely to be replaced or rescheduled, leaving April an empty month for the series and the championship reduced to 22 rounds.
Bahrain was scheduled for April 12 with the Saudi race, in Jeddah on April 19. The two races were last year won by Australian Oscar Piastri amid an early-season three-race win streak.
The Japanese Grand Prix, round three, is on March 29 with the next race then in Miami on May 3.
"I think we follow the guidance of the FIA and Formula One, as we always do. They've always led us in the right direction," Audi team principal Jonathan Wheatley told reporters after practice at the Shanghai circuit.
"Nobody's going to compromise on anything that would put teams into an uncomfortable situation."
There was no immediate comment from Liberty Media-owned Formula One or the governing International Automobile Federation (FIA).
MotoGP is due to race in Qatar on April 12 with that round also likely to be cancelled.
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