Syrian President Bashar Assad opened talks with Iranian officials Wednesday in a visit expected to include an appeal to free a French academic accused of plotting to overthrow the Islamic regime.

Assad is a close Iranian ally and also is using the trip to personally congratulate Iran's president, Mahmoud Ahmadinejad, on his re-election, which touched off massive unrest after opponents claimed the results were rigged.

One of the pro-reform challengers in the June 12 vote, Mahdi Karroubi, said he was ready to present evidence that some protesters were raped in custody.

Parliament, meanwhile, is awaiting the formal list of the president's Cabinet nominees, which could bring another wave of demonstrations.

But much of the international attention will focus on whether Assad lobbies for the release of Clotilde Reiss, a French academic on trial with more than 100 politicians, journalists and activists accused of trying to engineer a "velvet revolution" to overthrow the Islamic leadership.

Reiss was released last week on bail, but judicial authorities have barred her from leaving the country.

France last week thanked Syria for helping win the release from jail of a French-Iranian employee of the French embassy in Tehran, who is also in the same mass trial.

Syria carries considerable weight with Iranian officials as Tehran's closest Arab ally.

Releasing the French academic could be seen by Iran's leadership as a chance to win some international goodwill after facing allegations of torture and other abuses against demonstrators.

Karroubi issued a letter to Parliamentary Speaker Ali Larijani saying he was prepared to meet with top officials, including Ahmadinejad, to present testimony and other material to bolster the rape claims. The letter was posted on his party's Web site.

Karroubi, a former parliament speaker himself, said he has received reports of rapes from detainees released from jail as well as from former military commanders and other senior officials. Karroubi claims the abuses took place at Tehran's Kahrizak prison, which was ordered closed earlier this month.

But Larijani has rejected Karroubi's claims and other hard-liners have called for the arrest and trial of Karroubi for making the allegations.

Karroubi slammed Larijani's speedy denial, saying no probe could have been completed that fast. He has also vowed he won't remain silent over the "medieval torture and corruption" in Iran's prisons.

Some conservatives have also demanded a full investigation, leading to splits in Ahmadinejad's base of support.

"I demand from you to hold a meeting ... so that I can personally present my documents and evidence on cases of sexual abuse in some prisons," Karroubi said in the letter.

He has alleged that some detainees were "forced to go naked, crawl on their hands knees and knees like animals, with prison guards riding on their backs." Others were forced to lie "naked, on top of one another" — drawing parallels to the U.S. military abuses of detainees at Iraq's Abu Ghraib prison.

On Monday, Iran's prosecutor general ordered the closure of the pro-reform newspaper Etemad-e Melli after it ran articles on Karroubi's rape allegations. Karroubi heads the political party that runs the newspaper. The prosecutor gave no word on the length of the closure.