On the first day of the Unified State Exam answer sheets were posted online and students in a number of schools were disqualified for cheating, a news report said.
The exam season began on Monday with the Russian language exam set at all schools across the country. Due to time differences, pupils in the far east were able to upload copies of answer sheets to social networks in time for other pupils use them, Interfax reported.
In Belgorod, 650 kilometers south of Moscow, students discovered copying answers from their mobile phones were "removed from the exam, and their results were annulled," according to the local Education Department's website.
The fates of the disqualified students will now be decided by the State Exam Commission, but the rules indicate that they will have to wait until next year to retake the exams.
Dmitry Livanov, the education minister, said that the authorities can use the copies that have appeared online to find out who is responsible, before adding that those caught would be severely punished.
The Federal Service for Supervision in Education and Science warned that many of the published materials were fraudulent, and that students should refrain from using them.