The Federal Constitutional Court ruled that the parliamentary committee probing into the foreign ministry's failure to tighten revised visa rules must go on until the next elections, expected to be held in September.

The ruling came in response to an emergency petition from the conservative opposition, which wants the inquiry to continue.

The committee has been looking into allegations that an easing of visa regulations -- especially at Germany's embassy in Ukraine -- allowed in tens of thousands of illegal eastern European immigrants between 2000 and 2003.

Government representatives, who'd hoped to postpone further investigations until after the election, reacted angrily to the court's decision.

Elections deadline

The inquiry aims to ascertain whether the governing coalition's visa policies encouraged illegal immigration, moonlighting and human trafficking.

The center-left government had argued that the parliamentary probe must under German law be completed ahead of possible new elections, set to take place 12 months ahead of schedule.

Following that logic, the coalition parties said that testimony before the committee, which was formed in December, must be wrapped up now to allow it time to reach its conclusions.

But the federal tribunal ruled that the committee must continue to hear witnesses according to schedule until President Horst Köhler rules whether to order new elections -- a decision expected by July 22.

Fall-out for Fischer

Foreign Minister Joschka Fischer of the Greens party has seen his once impressive popularity ratings plummet in the wake of the affair and admitted before the committee in April that he had failed to take swift action when the problems became apparent.

Committee leaders have said they would like Fischer to testify again and call Interior Minister Otto Schily and other top officials as witnesses.

Schröder decided to call a no-confidence vote and prompt new elections after the latest in a series of bitter state poll losses last month.

His Social Democrats are trailing far beyond the opposition conservative Christian Union parties in opinion polls and the embarrassing probe will now likely continue well into the election campaign.