TEHRAN (Reuters) -- Iran's supreme leader called on the opposition today to distance itself from the Islamic republic's Western enemies, in a warning ahead of expected new antigovernment protests next month.
Tension has risen in Iran after eight people were killed in clashes between the security forces and opposition supporters on Ashura, the ritual day of Shi'ite mourning that fell on December 27.
It was the worst violence in the major oil producer since the aftermath of last year's disputed presidential election and was followed by the arrests of scores of pro-reform figures in a fresh crackdown by the authorities.
Despite intensifying pressure, opposition backers are expected to take to the streets again on February 11, when Iran marks the 31st anniversary of the 1979 Islamic Revolution.
Opposition Iranians have seized on occasions marked in the Islamic revolutionary calendar to revive their protests and messages of rallies on that day have circulated on the Internet.
Supreme Leader Ayatollah Ali Khamenei, who has effectively sided with hard-liners urging tougher action against the demonstrators, said Iran's foes were seeking to harm its unity.
Government officials have portrayed the huge opposition protests that erupted after the June election as a foreign-backed bid to undermine the clerical leadership.
"All parties with different tendencies should clearly distance themselves from the enemies, particularly influential elites should avoid making ambiguous comments," Khamenei said in a speech reported by state television.
Referring to the state-sponsored rallies usually on the revolution anniversary, he said the "enemies are worried about the huge presence of our nation" on that day.
But in a sign of continued opposition defiance, reformist former President Mohammad Khatami accused the authorities of launching a "new wave of pressures" and he defended people still protesting over the outcome of the election.
Khatami's comments, reported by the pro-reform Parlemannews website, are likely to anger ruling hard-liners who have repeatedly issued stern warnings against any more such rallies.
"Unfortunately we are witnessing these days a new wave of pressures and a new round of arrests," said Khatami, who backed opposition leader Mir Hossein Musavi in the presidential poll. He was speaking at a meeting of freed postvote detainees.
The June vote, which reformist leaders said was rigged to secure President Mahmud Ahmadinejad's reelection, touched off the worst internal crisis in the Islamic state's three-decade history. The government denied opposition charges of vote fraud.
Thousands of people, including senior reformers, were detained after the poll for fomenting unrest. Most of them have since been freed, but more than 80 people have been jailed for up to 15 years and five have been sentenced to death.
Iran's internal turmoil also added to tension with Western powers who accuse Tehran of seeking to develop nuclear bombs, a charge Iranian officials deny.
Khatami, who was president from 1997-2005, said those handling Iran's affairs had "done nothing but caused more problems," in hard-hitting criticism of Ahmadinejad's conservative government.
"The people have realized that many of the protesters were not ill-wishers and their protests were right," Khatami said. "The major part of the protesters are committed to the constitution and peaceful ways to voice their protests."
The government and state media regularly denounce people who demonstrate as "rioters" setting fire to public property.
An Iranian news agency, ILNA, today cited police as saying that tipoffs from the public had helped the force to arrest 40 "rioters" who took part in last month's protests.
The arrests followed the detentions of hundreds of people on Ashura itself. On January 18, five people went on trial in a Tehran court on charges that could be punishable by death.