The Washington Post has filed an urgent petition with the United Nations in the hopes that the institution will pressure Iran to release journalist Jason Rezaian, the newspaper's top editor and lawyers told U.S. reporters on Wednesday.

Rezaian was arrested over a year ago and held for months in solitary confinement without charges in Iran's Evin Prison. The Post's lawyers and his family say Rezaian has lost 50 pounds since his arrest and remains under severe psychological strain. His supporters had hoped that the conclusion of U.S.-led talks on Iran's nuclear program last week would pave the way for his release, speculating that he might have been detained by Iran as leverage in the negotiations.

"Every aspect of this case — his incarceration, his trial, the conditions of his imprisonment — has been a disgraceful violation of human rights. And it violates common decency," Post Executive Editor Martin Baron said at a news conference at the National Press Club.

U.S. officials said they insisted upon keeping the nuclear talks separate from discussions about Rezaian and other U.S. prisoners held in Iran in case the negotiations faltered — a tactic Rezaian's brother, Ali, said he supported. Still, Secretary of State John Kerry has said U.S. officials raised the issue of captive Americans with Iran persistently during the nuclear deliberations. But Rezaian remains in jail without another trial date publicly scheduled.

The Post petition was filed with a U.N. working group that focuses on unlawful detentions. The Post's lawyers said Iran has been responsive to about a third of the cases filed with the working group in the past decade. Jay Kennedy, the newspaper's general counsel, said the tactic hadn't been tried sooner because "we never expected his detention to last this long."

In the Iranian capital, Tehran, Deputy Foreign Minister Abbas Araghchi told reporters on Wednesday that cases of "imprisoned citizens" were discussed with their American counterparts during the nuclear talks. He said "humanitarian" reasons had motivated the discussion but did not elaborate.

It was the first confirmation by the Iranians of any talks that may have involved the fate of Rezaian and other U.S. prisoners in Iran: former U.S. Marine Amir Hekmati, Christian pastor Saeed Abedini, and retired FBI agent Robert Levinson.