CAIRO - Egypt's army imposed an overnight curfew around the defence ministry in Cairo on Friday after protesters clashed with troops there during demonstrations against military rule and the exclusion of candidates from the presidential election.The crowd hurled projectiles and insults at the soldiers sent to defend the ministry after 11 people were killed in fighting there on Wednesday, and called for the overthrow of the head of the ruling army council, Field Marshal Hussein Tantawi.Violence continues as night fallsAs dusk approached, gunfire rang out from the top of a mosque in Abbasiya. Army special forces climbed the minaret, brought down 10 people and drove them away.The pro-democracy Sixth of April Youth movement said on its Facebook page its followers were withdrawing from the Abbasiya area because of the bloodshed.Protesters regrouped closer to the town center after dark, waiting to return to the Defense Ministry, and some threw rocks and stones at troops blocking their path, state media reported.The one-night curfew will last from 11 p.m. local time (2100 GMT) to 7 a.m. on Saturday, the military council said in a statement read out on state television.The army "calls on all citizens to adhere to this or the military will confront with determination those who try to violate it," it said, vowing legal action against those responsible for the unrest.Some election candidates suspended their campaigns on Wednesday after unidentified assailants fired at protesters camping near the Defense Ministry, starting clashes that the security forces seemed unable or unwilling to quell.Many of those protesters were hardline Salafi Islamists upset that their candidate was ruled out of the vote, which begins on May 23 and 24 with a run-off in June.The Muslim Brotherhood, which dominates parliament, saw its first choice disqualified too, handing a potential advantage to Mubarak-era contenders such as former foreign minister Amr Moussa and ex-prime minister Ahmed Shafiq.Some Egyptians see the last-minute changes to the candidate line-up as proof the generals are trying to manipulate the vote."Remnants of Mubarak's regime are not eligible to assume any power," Hashem Islam, a sheikh from Egypt's highest authority of Sunni Islam, Al-Azhar, told protesters at the defence ministry.Several thousand Islamists, liberals and left-wing revolutionaries also massed on Friday in Tahrir Square, headquarters of the street movement that has transformed decades of tightly-controlled Egyptian politics.Banners draped in Tahrir demanded implementation of a law banning figures from the Mubarak era from high office. Shafiq was briefly disqualified as a result of the law, but still found his way back into the final line-up of presidential candidates.Members of the ruling military council on Thursday renewed a pledge to exit politics after handing power to the new president by mid-year. They said the handover could come earlier in the unlikely event that one candidate wins outright in the first round.But tension between the army's interim government and the Islamist-dominated parliament has left Egypt in a state of policy paralysis that is deepening an economic crisis caused by more than a year of political turmoil.Mohamed el-Beltagy, a senior figure in the Muslim Brotherhood's Freedom and Justice party, said the violence since Wednesday was the result of a deliberate policy to draw an unpredictable reaction from protesters and delay Egypt's political transition."This was done so that they (the authorities) could carry out emergency measures," he said.The army fired back water cannon then teargas and riot police surged towards the crowd with batons. Scores of wounded protesters were taken away on motorcycles and dozens of soldiers were injured."Field Marshal leave. The people are dangerous," shouted the crowds, and "Raise your voice. Our revolution will not die."The street violence comes less than three weeks before an election that represents the first chance for Egyptians to freely choose their leader. A successful vote would mark the most important step in a messy transition to democracy since the overthrow of autocratic leader Hosni Mubarak 15 months ago.Last-minute changes to the line-up of contenders, bickering over a new constitution and suspicion that the military will continue wielding power after a new president is chosen are making for a chaotic backdrop to the campaign.The troops pressed forward when protesters began cutting through barbed wire used to seal off the ministry building in Cairo's central Abbasiya district.Protesters ripped down a metal fence at an underground railway construction site to build a barricade. Some cried "God is Greatest" as army helicopters swooped overhead.The teargas scattered the crowd far down the rock-strewn streets. Troops blocked off several streets between Abbasiya and central Cairo using armored personnel carriers and some fired shots in the air.The Health Ministry said 128 people were wounded, state news agency MENA reported. The injuries included teargas inhalation and cuts and bruises, some serious, and 82 people were taken to hospital."The crowd is coming here with sharp weapons. We have batons and water cannon and teargas to disperse them," said one commander. "Some of them believe if they kill a soldier they will go to heaven. What do you expect us to do?"