France and Germany oppose newcomers to border-free area

The ministers said it was "premature" to let the two countries join Schengen in March - the current date aimed for by the two countries - and recommended that the EU wait for "irreversible progress" in the fight against corruption and organised crime instead.

Back in Berlin, a spokesman for Germany's interior ministry said that lack of progress by Romania and Bulgaria in reforming their judiciaries could have "grave consequences for the European Union's security" and raised concerns about an "overly swift" adhesion to the Schengen area, AP reported.

Romanian President Traian Basescu reacted to the letter saying it was "an act of discrimination against Romania" which his country would not tolerate, even if it comes from "EU's most powerful countries".

In practice there is little Bucharest can do, as the decision has to be agreed unanimously among Schengen members - 22 EU states plus Norway, Switzerland and Iceland - meaning that France and Germany have veto powers.

Meanwhile, a more compliant Bulgarian foreign ministry spokeswoman said her country would "do the utmost to remove any doubts, including in the areas of the judicial system and society as a whole".

The two newcomers had so far painfully tried to avoid a link between a unique EU monitoring system put in place after they joined the bloc in 2007 and evaluating their fight against crime and corruption, with their bid to become members of the border-free area.

So far, the EU commission had maintained that the two processes are not linked and that Schengen enlargement has its own evaluation system, but has also conceded that it is "a matter of trust" with other states in the area, which will depend on the newcomers to secure their common borders.

Experts evaluating the readiness of the countries two have so far given them a green light, with a final report due in January.