TEHRAN: Iran put 16 opposition supporters detained during anti-government protests last month on trial Saturday on charges of rioting and conspiring against the ruling system, Iran's state media reported.

The official IRNA news agency and state Press TV said the defendants face charges ranging from plotting against the establishment to violating security regulations. Five of those on trial, including two women, were accused of "moharebeh," or defying God, a charge that could carry the death penalty, the semiofficial ISNA news agency reported.

The new prosecutions, coupled with the execution on Thursday of two men accused of involvement in anti-government groups, could mark an attempt by Iran's hardline leaders to intimidate the opposition ahead of a new round of street demonstrations expected in February.

Those who stood trial Saturday — including a follower of the Bahai faith, an alleged communist and a student activist — were detained during anti-government demonstrations on Dec. 27, when at least eight people were killed and hundreds more were arrested after clashes between opposition activists and security forces. The violence was the worst since authorities launched a harsh crackdown immediately after Iran's disputed presidential election in June.

The protesters have presented Iran's cleric-led establishment with its biggest challenge since the 1979 revolution despite a brutal crackdown that has left hundreds imprisoned.

IRNA quoted a prosecutor identified only by the last name of Farahani as saying in court that some of the defendants had confessed to spying, planning bomb attacks and damaging public and private properties. He also said some of the defendants had sent videos on the clashes between protesters and Iranian police to the "foreign hostile networks," IRNA reported.

During previous mass trials in Iran, many human rights groups have cautioned that such confessions are often made under duress in Iran.

The ISNA news agency quoted the student activist, who was not named, as telling the court Saturday that he had given interviews to the foreign media about the protests since the "doors of the domestic media are closed to us."

Iranian authorities have banned many newspapers and news Web sites and detained many opposition journalists after the election.

The new trial comes amid a sweeping crackdown by Iran's clerical leaders against opposition activists in a bid to crush the challenge that has emerged to their rule in the wake of President Mahmoud Ahmadinejad's disputed re-election in June. The opposition says Ahmadinejad's victory was fraudulent.

Iran's hardline government has quashed opposition rallies and tried more than 100 political activists since August, sentencing 11 people to death and more than 80 people to prison terms ranging from six months to 15 years.

Saturday's trial comes days after the authorities hanged two men who had been convicted of belonging to "counterrevolutionary and monarchist groups," plotting to overthrow "the Islamic establishment" and planning assassinations and bombings.

The men were arrested months before the election.

But they were put on the same mass trial as around 100 opposition activists, protesters and politicians who were arrested in the postelection crackdown — an attempt by the leadership to show that the political opposition is in league with violent armed groups in a foreign-backed plot to overthrow the Islamic system.

Iran held its first postelection mass trial in August, accusing more than 100 activists of plotting to overthrow the regime. Those prosecutions brought charges against some prominent reformist opposition politicians, including former Vice President Mohammad Ali Abtahi, former government spokesman Abdollah Ramezanzadeh and the leader of the biggest reformist party, the Islamic Iran Participation Front, Mohsen Mirdamadi.

There were also three foreign citizens — Iranian-American scholar Kian Tajbakhsh, Newsweek reporter Maziar Bahari, who holds Iranian and Canadian citizenship, and a 24-year-old French academic, Clotilde Reiss — among those on trial. Bahari has since been released on bail and has left the country.

Despite the crackdown, opposition activists have continued to hold sporadic, large street rallies. The opposition says Ahmadinejad's victory in the June election was fraudulent and call for his removal — though some in the movement have expanded to criticize Iran's clerical leadership.