Four brothers jailed for almost three years for allegedly supporting terrorists are not a danger to national security and cannot be deported to Iran, an immigration appeals board has ruled.

But it was a bittersweet victory for the Mirmehdis -- Mohammed, Mostafa, Mohsen and Mojtaba -- who were arrested Oct. 2, 2001, and are also challenging Attorney General John D. Ashcroft's decision to hold them without bond. The men had worked in real estate in Los Angeles before their arrests.

Evidence tying the Mirmehdis to terrorism was inconclusive, the U.S. Board of Immigration appeals ruled. Federal prosecutors had argued that the brothers' support of the Mujaheddin-e Khalq, an Iranian opposition group that was on the State Department's list of terrorist organizations, made them a national security threat.

In the ruling, the board upheld the decisions of two immigration judges who said the Mirmehdis would be persecuted if they were returned to Iran. But the panel agreed with the government that they did not qualify for political asylum, because they lied on their applications for asylum in 1999.

"We are still in limbo," said Mohsen Mirmehdi. The men's lawyer, Stacy Tolchin, said the ruling means the Mirmehdis could legally be freed from custody within 90 days.