If Virant refuses to step down, the party will demand an extraordinary session of the National Assembly to discuss the work of the National Assembly and the speaker, PS head Zoran Jankovć told the press after a meeting of the party council.

The PS believes that in the process of checking signatures submitted by a trade union as part of a referendum initiative for the bad bank act, it fell victim to "organised fraud".

Virant responded that there was no reason for him to resign. "There is no proof that the mistake...occurred at the National Assembly. On the contrary, the National Assembly has detected and resolved the problem," he told the STA.

Janković said it was time that the ruling Democrats (SDS) give up the Interior Ministry, thus respecting the wish of Virant, who insisted loudly at the beginning of the year that SDS should not hold this portfolio.

When asked whether his party has already formed an alternative, Janković said that first the National Assembly needed to prove that it is independent enough to condemn this incident in a no-confidence vote. "If this happens, we will propose an alternative."

The call comes after the National Assembly found a discrepancy between the number of signatures filed by the trade union and the number of signatures checked by the Interior Ministry.

The ministry rejected the suspicions that it had misplaced some 400 signatures, rendering the referendum initiative invalid, while the National Assembly filed a criminal complaint against an unknown perpetrator.

The signatures sent into verification to the ministry were copies, while the originals are still kept at the National Assembly.

Similar to the PS, the opposition Social Democrats (SD) urged Gorenak to resign today.