Protesters and soldiers clashed in Egypt Friday, as thousands rallied against the country's ruling military council prior to landmark presidential elections later this month.

Medical sources say at least 40 people were wounded in the violence near the Defense Ministry in Cairo's Abbassiya district.

Egypt's ruling military late Friday announced a curfew in the area surrounding the defense ministry where mostly Islamist protesters have been camping for days, demanding an immediate end to military rule.

Demonstrators threw rocks at the soldiers, who responded by firing tear gas and water cannons. Some protesters set fires. The soldiers eventually chased the demonstrators out of the area. Smoke was rising from the scene after dusk.

The violence comes two days after fighting in Cairo left at least 11 people dead and more than 100 wounded, and prompted the two top Islamist candidates for the presidency to suspend their campaigns.

Egypt's presidential election is scheduled for May 23 and 24. The military rulers have vowed the elections will be fair.

The election will be the first since a popular uprising ousted longtime autocratic leader Hosni Mubarak more than a year ago.

The military council that took over from Mr. Mubarak has promised a democratic transition and a transfer of power to an elected president by July 1. But Egypt's generals have faced strong domestic criticism for their handling of that process, which has been plagued by periodic eruptions of deadly violence, often surrounding anti-government protests in major cities.

Islamists are angered by the ruling military's decision to bar ultraconservative Islamist cleric Hazem Abu Ismail from standing in the presidential contest. Egypt's election commission disqualified Abu Ismail because his mother had taken joint U.S. citizenship.