"Such a change is much broader and makes more sense because it covers all first degree murders. These are our positions and the starting point," a source from the ruling coalition's junior partner told the media on Monday.

In early July, the HNS was against changing the Constitution, saying frequent changes were not good and that only three years had passed since the last changes were made.

According to unofficial reports at the time, the party believed that lifting the statute of limitations on politically motivated murders could be secured in an another way, for example by expanding the catalogue of criminal acts.

HNS president Vesna Pusic later said that lifting the statute of limitations on politically motivated murders 20 years after Croatia gained independence would result in lustration, which was unacceptable to the party.

Seeing that Milorad Pupovac of the Independent Democratic Serb Party (SDSS) has told the Novi List daily that the SDSS would back "modified" constitutional changes, the ruling SDP has enough votes to initiate them.

After one-fifth of MPs move constitutional changes, parliament decides by a majority of all MPs if the changes will be made. A draft of the changes is also formulated by a qualified majority, but the final changes are decided by two-thirds of all MPs, which means that the Constitution cannot be changed without the strongest opposition party, the Croatian Democratic Union (HDZ).

The HDZ reiterated today that it was unacceptable to compare individual murders with those incited and committed by the regime. The latter are "state terror," HDZ spokeswoman Silvana Oruc Ivos told the press.

The HDZ has said earlier that it will not agree to constitutional changes unless the law on the European Arrest Warrant was applied fully and without delay. The party will not agree to the changes even if the government reaches an agreement with the European Commission to delay the application until July 2014, as requested by the government, or until January 2014, which has unofficially been announced as a possible compromise.

The HDZ does not believe such an agreement is possible, especially after German Chancellor Angela Merkel said today that she hoped Croatia would honour what it had agreed with the EU.

Oruc Ivos said the HDZ's rejection of constitutional amendments could not be interpreted as protection of former Yugoslav intelligence officer Josip Perkovic, who is wanted in Germany, "because for his extradition it is enough to change the law."