Iran's opposition leader asked authorities Sunday for permission to hold a memorial service for victims of last month's post-election unrest, including a young woman whose death was caught on video and became a symbol for protesters, said the leader's top aide.

Iranian authorities have pressured the families of slain protesters not to mourn publicly out of fear the gatherings could spark the kind of demonstrations that followed the June 12 presidential vote. Hundreds of thousands of supporters of opposition leader Hir Hossein Mousavi took to the streets to protest President Mahmoud Ahmadinejad's disputed victory.

Despite the regime's violent crackdown that killed at least 20 people and Supreme Leader Ayatollah Ali Khamenei's demand that the opposition drop it's claims of massive vote fraud, Mousavi and his supporters have kept up the pressure by criticizing the state's harsh response and reaching out to top clerics for support.

Looking for other ways to keep pressure on the regime, Mousavi and fellow pro-reform presidential candidate, Mahdi Karroubi, sent a request to the Interior Ministry to hold a memorial service in Tehran's main mosque Thursday to commemorate the end of the 40-day mourning cycle for at least 10 people killed on June 20, said Mousavi's top aide, Ali Reza Beheshti.

One of those killed was Neda Agha Soltan, a 27-year-old woman shot to death during a Tehran demonstration. Her dying moments on the street were caught on a video viewed by millions on YouTube, and she became an icon in the opposition's struggle.

Soltan's family has said that the volunteer Basij militia, whose members have been accused of shooting the young woman and other protesters, denied Soltan a formal funeral. Iranian authorities have denied that the Basij was behind the killing.

Mousavi and Karroubi attempted to assuage concerns that the requested memorial would spark additional unrest, saying it "will be held without any speeches and will be limited to the reciting of the Koran (the Muslim holy book) and moments of silence."

The regime's concern about unrest has historical precedence. The deaths of protesters during the 1979 Islamic Revolution fueled a 40-day cycle of mourning marches, and shootings of mourners, that contributed to the overthrow of the U.S.-backed dictator, Shah Reza Pahlavi.