“Krstajic, 45, was fired by the national football organisation (FSS) committee for emergency issues, and a new coach will be named by July 10,’’ the reports said.
However, the FSS has not issued a statement yet.
Serbia trails Ukraine with 10 points and Luxemburg with four in Group B, with four points from three matches, including an away draw with Portugal in March.
Krstajic’s days were, however, widely seen as numbered after recent dismal performance and a 5-0 defeat to Ukraine.
A 3-0 win over Lithuania, who has no points yet, on Monday was not enough to save his job.
Krstajic has faced persistent criticism ever since he took over from Slavoljub Muslin as caretaker in Oct. 2017.
He was eventually given a permanent job at least until the end of the 2018 World Cup, the country’s first in eight years.