A German man who says he was illegally detained and tortured in overseas prisons run by the CIA is appealing a federal judge's dismissal of his lawsuit.

Lawyers for the American Civil Liberties Union, which is representing Khaled al-Masri, filed the appeal Monday with the 4th U.S. Circuit Court of Appeals. Al-Masri's lawsuit names former CIA director George Tenet as a defendant, as well as several private firms that helped transport al-Masri to Afghanistan.

In May, U.S. District Judge T.S. Ellis III in Alexandria tossed out al-Masri's lawsuit after the government intervened in the case and filed a secret brief in which it said the lawsuit could expose state secrets.

Al-Masri says he was kidnapped on New Year's Eve 2003 and detained for nearly five months before finally being dumped on an abandoned road in Albania after authorities learned he was a victim of mistaken identity. He spent part of that time in an Afghan prison known as the "salt pit" and says the CIA was responsible for his capture, torture and detention.

Ellis, in dismissing the lawsuit, made no finding about the validity of al-Masri's claims but said his lawsuit could not go forward.

"Al-Masri's private interests must give way to the national interest in preserving state secrets," Ellis wrote.

Al-Masri's lawyers argue that U.S. and European officials have already substantiated al-Masri's allegations in press reports, so there is no harm of divulging state secrets.

"The district court embraced an expansive and overbroad construction of the state secrets privilege that would virtually immunize the most egregious executive misconduct from judicial review," al-Masri's lawyers wrote in their appeal.