Protesters demanding the departure of Senegal’s aging president on Sunday seized control of a three-block stretch in the heart of the capital, erecting barricades and lobbing rocks at police just days before a contentious presidential poll.It marks the fifth day of violent protests ahead of the country’s crucial vote. President Abdoulaye Wade, 85, is insisting on running again, despite the deepening unrest and calls from both France and the United States to hand power to the next generation.Sunday’s clashes marked a worrying development, because they took on a religious dimension in this normally tolerant Muslim nation. Hundreds had gathered outside a mosque as religious leaders met to discuss a Friday incident in which police used grenade launchers to throw tear gas down the wide boulevard, at one point hitting the wall of the mosque.Footage of the incident shown on Senegalese TV indicated that the police had not shot inside the mosque, only outside where a crowd had gathered. But the cloud of gas enveloped worshippers praying both inside and outside the shrine, deeply offending Senegal’s largest Muslim brotherhood which owns the mosque.On Sunday morning as the crowd outside the mosque grew larger, a truck of riot police took a defensive position at one end of Lamine Gueye Boulevard, and the dozens of youths erupted in jeers. They then began grabbing cinderblocks from a nearby construction site, smashing them on the pavement in order to make smaller projectiles which they hurled at police. Security forces responded with waves of tear gas.They sparred for over 1 hour and by then, the protesters succeeded in seizing control of a three-block stretch of Lamine Gueye, one of two main commercial avenues traversing downtown Dakar. They grabbed market tables and pieces of plywood that had been nailed across shop windows, using them as shields to protect themselves from the tear gas grenades.