The Egyptian FA said on Twitter Salah had returned a positive test, although the 28-year-old is not showing any symptoms.
The governing body added the rest of the Egypt team were negative for coronavirus, while Salah is now self-isolating and will be “subject to more checks in the coming hours”.
Egypt host Togo on Saturday in an Africa Cup of Nations qualifier before playing the reverse fixture on Tuesday.
Liverpool are next in action against Leicester on November 22, a match Salah would miss under current UK Government guidelines despite being asymptomatic.
The Government website states: “If you do not have symptoms but have tested positive for COVID-19, stay at home and self-isolate for 10 days from the day the test was taken.”
It would also make him a doubt for the home Champions League tie against Atalanta on November 25 given he is unable to train with his club team-mates.
The news comes after Liverpool lost defender Joe Gomez to a long-term injury, although the club are hopeful the England international will return before the end of the season.
Right-back Trent Alexander-Arnold is expected to miss the Leicester match with a muscle injury, while Virgil van Dijk is out for the season after requiring knee surgery following a collision with Jordan Pickford in the Merseyside derby.
Salah is also the fourth Liverpool first-team player to test positive for coronavirus this season, following Thiago in September and then Sadio Mane and Xherdan Shaqiri in October.
Liverpool’s upcoming fixtures
- Nov 22: Leicester (H) – PL
- Nov 25: Atalanta (H) – CL
- Nov 28: Brighton (A) – PL
- Dec 1: Ajax (H) – CL
- Dec 5: Wolves (H) – PL
- Dec 9: Midtjylland (A) – CL