Karroubi is targeted by Tehran's hardliners

Iranian authorities have opened an investigation into the former presidential candidate Mahdi Karroubi, a report said yesterday, in a possible first step toward unleashing the judiciary on opposition leaders.

No formal charges have been filed, but the inquiry signals that Iran's leadership could use the courts against the most senior dissenters, whose claims include widespread vote fraud in June's disputed presidential elections and abuses by security forces against protesters in the violent aftermath.

It is likely the investigation would include Mr Karroubi's explosive accusations of abuses by security forces. He has led claims of rape and torture against protesters detained during the demonstrations and clashes following Mahmoud Ahmadinejad's re-election.

Mr Karroubi has demanded high-level investigations into the abuse claims. His newspaper, Etemad-e-Melli, was banned in August.

The powerful Revolutionary Guard and other pro-regime groups have pushed for charges against the top opposition figures, including Karroubi, his fellow reformist candidate Mirhossein Mousavi and the former president Mohammad Khatami. More than 100 activists and political figures have already been tried on a range of charges that include seeking to overthrow the Islamic system.

The official Islamic Republic News Agency quoted the Tehran prosecutor Abbas Jafari Dolatabadi as saying that an investigative file had been opened on Mr Karroubi and the case was under review by a special cleric court.

"Some individuals have already been summoned" as part of the inquory, said Mr Dolatabadi, a Shia cleric and former parliament speaker. He said that 10 more people would go on trial on charges related to the postelection turmoil. But the report gave no names or further details.

The Parliament Speaker, Ali Larijani, has denied the allegations of rape and other abuses, saying a parliamentary inquiry into the allegations had found no truth in the reports.

The judicial inquiry could be an attempt at further pressure to muzzle opposition. Efforts to bring charges would open a new front against senior reformists. They could face serious charges of "propagating against the Islamic system" which could result in long prison terms. The Special Cleric Court operates in secrecy and its proceedings are closed to the public.

Iranian authorities have faced international condemnation for the crackdowns that followed the June election, but attention has greatly shifted to the regime's negotiations with Western powers over its nuclear program. More talks are planned for this month.

* Russia appears ready to block US efforts to threaten Iran with tough new sanctions if Tehran fails to prove its nuclear programme is peaceful. The Russian stance is a setback to the Obama administration's desire to present a united front with Moscow.

After meeting the US Secretary of State, Hillary Clinton, the Russian Foreign Minister, Sergei Lavrov, said yesterday that Moscow believed such threats would not persuade Iran to comply and negotiations should continue to be pursued.