ZAGREB (Reuters) - Serbia must change its law on prosecuting crimes committed during the 1990s Balkan wars as a condition for completing European Union membership negotiations, Croatia said on Wednesday.

Croatia's new Minister of Foreign Affairs Miro Kovac is seen in parliament before the government was approved in Zagreb, Croatia, January 22, 2016. REUTERS/Antonio Bronic

More than a decade ago, Serbia passed a law claiming jurisdiction over war crimes committed on the entire territory of the former Yugoslavia that crumbled during the wars.

That includes Croatia, which fought a 1991-95 war against Belgrade-backed Serb rebels to forge its independence from Yugoslavia.

“Serbia cannot be some sort of judge in war crimes for all the countries of ex-Yugoslavia, including Croatia. It is unacceptable and it will have to be part of (EU) negotiation benchmarks that Serbia must meet,” Croatian Foreign Minister Miro Kovac told reporters after a cabinet meeting.

Any country wishing to join the 28-nation EU must go through a complex negotiation, bringing its laws into line with those of the EU in 35 policy areas or chapters.

Croatia joined the EU in 2013 whereas neighboring Serbia only opened negotiations on its first two chapters last December. Belgrade hopes to open two more chapters, on judiciary and law enforcement issues, before the end of June, and aims to wrap up the entire negotiations by 2019.

All EU members must agree to chapters being opened or closed, giving Croatia an effective veto on Serbia completing the membership talks.

Other conditions that Serbia should have to fulfill in the EU membership talks were full compliance with a bilateral agreement on the protection of minorities and full cooperation with the U.N. war crimes tribunal in The Hague, Kovac said.

Belgrade says it already cooperates with the U.N. tribunal and has sent suspects to The Hague including wartime Bosnian Serb leader Radovan Karadzic, who was sentenced to 40 years in prison last month for genocide. [ID:nL5N16W1OS]

Tanja Miscevic, who heads Serbia’s EU negotiating team, told state broadcaster RTS she understood Croatia was making amending the war crimes law a condition for Serbia to wrap up negotiations with the EU on judicial matters. She did not say whether Belgrade was prepared to change the law.

Serbia and Croatia have sought reconciliation over the last 15 years although the migrant crisis last year led to the neighbors trading embargoes and insults.