The committee was set up in April 2006 to investigate accusations that German secret service agents had assisted the US secret services in transporting, questioning and otherwise dealing with those captured during and after the Iraq war.

The court in Karlsruhe found that the government's restrictions on witnesses, as well as its refusal to supply certain files, breached the right of the Bundestag to have the information it needed to carry out its investigation.

Such restrictions cannot be justified by general reference to "central elements of executive responsibility" or "the good of the state," said the court. The government should have given specific reasons in each case.

It specifically criticized the Foreign Minister, Frank-Walter Steinmeier, the former Interior Minister, Otto Schily, and the head of the secret service BND, Ernst Urlau, for failing to give adequate reasons for refusing to answer questions.

The case was brought by the three opposition parties in parliament, the Greens, the Liberal FDP and the Left party. They complained that they were hindered from investigating the kidnapping of the Lebanese German Khaled el Masri, the abduction and imprisonment in Guantanamo of the German-born Turk Murat Kurnaz, and the abduction and imprisonment of the Syrian German Islamist Haydar Zammar in Damascus.

The liberal spokesman on the parliamentary committee, Max Stadler, told a German newspaper that he had already called for a special sitting of the committee to take some of the evidence which had been withheld.

Spokesmen for both the Greens and the Left said however they would perhaps prefer to leave further investigation to a committee to be set up after the new parliament is elected on September 27.

The committee chairman, the Christian Democrat Siegfried Kauder, said that the committee could not be revived, since it had delivered its report and been wound up. "I would have preferred it if the decision had come down before the committee had finished its work," he told the Mitteldeutsche Zeitung newspaper. "I certainly don't want to criticize the court. But this outcome is definitely not good."

mll/dpa/Reuters/AP/AFP
Editor: Neil King