An Iranian court has convicted another opposition activist on charges related to the country's post-election turmoil and sentenced him to death, the judiciary said Tuesday.

The sentencing brings to at least 10 the number of those facing the death penalty in a mass trial over the unrest following Iran's disputed June presidential elections.

The Web site of the country's judiciary said the activist was convicted of Moharebeh, or defiance of God, and handed the capital punishment. The report also said that eight more people were sentenced to unspecified prison terms.

The eight were arrested following deadly clashes in late December between opposition protesters and security forces, it said. The report did not identify those convicted or say when they were sentenced.

The Web site also said that an appeals court has upheld earlier convictions and sentences for 35 opposition activists. Those included a five-year sentence for Behzad Nabavi, a deputy parliament speaker in the 1990s and a close ally of opposition leader Mir Hossein Mousavi.

Nabavi also served as deputy prime minister in the early 1980s when he negotiated with U.S. officials the release of American hostages held in the 1979 takeover by militant students of the U.S. embassy in Tehran.

Iran has already put more than 100 people on a mass trial that began in August as part of the crackdown on those challenging the election in which President Mahmoud Ahmadinejad was declared the winner. Along with the 10 death sentences, more than 80 of those on trial have been handed prison terms ranging from six months to 15 years.

Last month, Iran executed two men who were part of the mass trial, although they were detained before the June election for alleged ties to a foreign-based armed opposition group.

Also Tuesday, authorities released from detention two prominent opposition figures — Ali Reza Beheshti and Mohammad Reza Tajik. The two had been detained for months on charges related to the election unrest.

There was no word on why they were released or whether the charges against them have been dropped.

At least eight people were killed and hundreds were detained in the Dec. 27 clashes, the last in a series of major street confrontations between the opposition and the government that erupted in the wake of the June balloting.

The opposition alleges Ahmadinejad won the vote through massive fraud and that Mousavi is the rightful winner.

Earlier Tuesday, an opposition Web site said authorities detained a nephew of Mousavi's wife. The Kaleme site said Mohammad Saleh Noqrehkar was arrested Monday after he was summoned to Tehran's Evin prison.

Noqrehkar is also Mousavi's legal adviser who until last month worked as a spokesman for Iran's prosecutor office.

The late December clashes were the worst unrest since the immediate aftermath of the June election. Among the eight killed was Mousavi's nephew, Ali Mousavi. He was gunned down but authorities later said police didn't use firearms and said the nephew was "assassinated" by unknown assailants.

Another person close to Mousavi, his brother-in-law Shapoor Kazemi, was released in January after spending five months in detention. Kazemi is an engineer who is not involved in politics.

The opposition believes the detentions are an attempt to pressure Mousavi and the opposition movement.

Iran is bracing for expected protest marches Thursday to coincide with events marking the anniversary of the 1979 Islamic Revolution.