The head of Serbia's state lottery has resigned following allegations of a fraud during a live ticket draw this week.

Police said Thursday they have questioned six people during an investigation into whether the latest winning lottery combination had been set up in advance.

The affair erupted when on Tuesday evening live broadcast one of the numbers in the winning combination appeared on TV screens before it was actually drawn. This sparked accusations that the numbers had been chosen in advance.

The State Lottery has denied fraud and blamed the incident on a "technical mistake." The company head, Aleksandar Vulovic, said Thursday he was stepping down out of "moral obligation."

Lottery is very popular in Serbia, a Balkan country with a poor economy and widespread corruption.