BEIRUT — Iran's leading opposition figure called on his supporters Monday to head into the streets daily during a religious festival next week, potentially escalating tensions at a time when his election rival, President Mahmoud Ahmadinejad, is to be sworn in for a second term.
The call for new protests was the most provocative move in weeks by former Prime Minister Mir-Hossein Mousavi. It was a sign that the aging bureaucrat, once a pillar of the Islamic Republic's political establishment, is growing into the role of leader of a youth-based movement that seeks greater democracy and better ties to the rest of the world.
It also highlights the difficulty Iran's political powers are having trying to tame the unrest stemming from charges that Ahmadinejad stole the June 12 presidential election. Authorities have fallen back on the same tactics they used to quell protests in 1999 and 2003 -- beating and imprisoning activists. But this time, those methods have not stopped the protest, and have even divided the ranks of political conservatives.
A legislator said Sunday that Ahmadinejad would be sworn in for his second term on Aug. 5.
Mousavi said in comments to educators published on his website, Ghalamnews.ir, that the religious festivities, which should take place over several days during the middle of next week, were an opportunity to extend the political movement outside the capital.
"We must express awareness among the people," he said. "We must raise slogans that can include all Iranians both inside and outside the country.
"A vast . . . social movement has taken shape in the country and it has to make best use of these occasions and unveil its initiatives," Mousavi said. "We can organize programs each day to follow up on our objectives."
It was the first time Mousavi had explicitly called on his supporters to take to the streets since a series of massive protest marches last month. Dozens of Iranians have been killed and hundreds arrested in clashes between protesters and security forces.
Iran's political powers seem at a loss as to what to do, and some political conservatives are incensed over Ahmadinejad's divisive political actions as well as the widespread crackdown. The supreme leader, Ayatollah Ali Khamenei, forced Ahmadinejad to back down on his choice of a first vice president.
Many conservatives were highly uncomfortable with the selection of Esfandiar Rahim Mashaei, who is related to Ahmadinejad by marriage. Some analysts said it was because of friendly comments Mashaei made about the Israeli people. But others said he is believed to be a member of a secretive messianic sect with a worldview so extreme that it was banned by Ayatollah Ruhollah Khomeini, the founder of the Islamic Republic.
Security forces' violent response to the postelection protests and harsh rhetoric make Mousavi's call to action all the more provocative.
Next week's festival celebrates the birth of the Mahdi, the last saint or imam of the Shiite faith, who disappeared as a child. Clerics say his return will herald a new age. The Shiite faithful sing, clap and light candles as they walk in celebration of the Mahdi's birth.
Opposition figures also are demanding to use Tehran's Grand Mosala Mosque on Thursday as a venue to commemorate the religiously significant 40th day after the deaths of protesters killed in June 20 demonstrations, including Neda Agha-Soltan, the young woman whose shooting was captured on video and seen around the world. Whether or not the mosque permit is issued, Iranians are bracing for fresh clashes on Thursday.
Mousavi condemned the government for unleashing a violent crackdown against supporters.
"We never wanted a regime allowing a bunch of plainclothesmen to launch nightly raids on our people and students and vandalize their properties," he said. "After the revolution, people punished those who committed crimes before the revolution, and today's criminals should bear in mind that our people will never pardon them."
Reformist news websites also reported Monday on another protester allegedly killed by security officials. Ramin Ghahremanian, 30, died of injuries allegedly sustained during 15 days of detention in Tehran's Evin Prison, his family told news outlets.
When he was released, he was covered with bruises and signs of abuse, and died two days later of his injuries, his relatives said. They have been ordered not to publicly mourn his death.
The fate of some of those arrested remains uncertain. Plainclothes security officers seized former Deputy Interior Minister Mostafa Tajzadeh at his Tehran home June 13, and no one has heard from him since.
"I am very worried," his wife, Fakhri Mohtashamipour, said in a telephone interview. "I'm afraid he is being tortured."
The crackdown has prompted outrage not only among human rights organizations, but prominent conservatives.