Egyptian protesters prepared to spend the night in Cairo's Tahrir Square late Wednesday after tens of thousands had gathered earlier in the day to mark one year since the start of an uprising that toppled long-time president Hosni Mubarak.

Many of those who attended the massive rally called it a celebration of the downfall of an autocratic leadership, but others said they want a new revolution against the military rulers who took over when Mr. Mubarak was ousted.

Several pro-democracy groups in the square announced they would begin a sit-in until Friday when another rally is planned.

Officials of Egypt's main Islamist group, the Muslim Brotherhood, were among those cheering in the square. The movement's political arm is one of the main beneficiaries of last year's revolution, winning the largest share of parliamentary seats in free elections organized in recent months by Egypt's ruling military council.

The Brotherhood has rejected calls for a new uprising against the military and endorsed the council's timetable for a handover to an elected president by the end of June. The group was officially banned during Mr. Mubarak's near 30-year rule, but its popular social services for the poor helped it to become the country's best-organized political force.

Liberal youth groups who led the 2011 revolt had a different message, chanting “down with military rule” as they marched to Tahrir Square. They accuse the military council of behaving like the Mubarak government by violently suppressing pro-democracy protests and trying civilians in military courts.

Egypt's military rulers have promised to hand over power after holding a presidential election by June. The military council led by Field Marshall Mohamed Hussein Tantawi has made several apparent concessions to reformists in recent days.

It has pardoned about 2,000 prisoners and promised to partially lift the country's 30-year-long state of emergency beginning Wednesday. But, the ruling military said authorities will continue to apply the widely-disliked law in fighting acts of “thuggery.” It did not elaborate.

The New York-based Human Rights Watch says the exception is an “invitation to continued abuse” and an “insult” to Egyptians calling for a return to the rule of law. It says Egypt's military rulers frequently have described “peaceful” demonstrators as “thugs” and put them on trial in military courts for the offense.

Tahrir Square was a focal point for the anti-Mubarak activists who began a series of mass protests for political and economic reforms on January 25, 2011. The activists continued protesting in central Cairo for 18 days, defying a deadly police crackdown until Mr. Mubarak ceded control of the government to the military council.