Official Bucharest has threatened to to create problems for Croatia's EU accession bid in a diplomatic counter-attack against delays to its own entry into the EU's border-free Schengen zone.

In an interview with the daily newspaper Adevarul on Monday Romanian Foreign Minister Teodor Baconschi criticised Germany and France for linking Romania’s Schengen bid to progress on corruption and organized crime.

"The same rules that were applied to any other enlargement of the Schengen area must be respected," Baconschi said, noting that Romania had been promised to get into Schengen when it met purely "technical" requirements.

"Let's have a look at Croatia's situation. We are supporting any EU enlargement to the western Balkans. But we can't accept that this is being done without (Cooperation and Verification Mechanism) CVM, as long as CVM is being kept in our case," he added in a thinly-veiled threat to hold Zagreb to ransom over the Schengen issue.

The so called CVM was imposed on Romania and Bulgaria in 2007 because the European Commission and other EU members wanted to pressure the two countries to keep-up anti-corruption reforms after they entered the Union.

Four years later, the mechanism is still in force, and Romania is still rated as one of the most corrupted European countries.