ISMAILIA/CAIRO - Thousands of Egyptian protesters ignored a curfew on Monday to take to the streets in cities along the Suez canal, defying a state of emergency imposed by Islamist President Mohamed Morsi to end days of violence that has killed at least 51 people.One man was killed in violence late on Monday in Port Said and another was shot dead earlier in Cairo as a wave of violence raged on, unleashed last week on the eve of the two-year anniversary of the popular revolt that brought down autocrat Hosni Mubarak.Political opponents spurned a call by Morsi for talks to try to end the violence, with main opposition groups refusing to attend a meeting.Instead, huge crowds of protesters took to the streets in the capital Cairo, Alexandria and in the three Suez Canal cities - Port Said, Ismailia and Suez - where Mursi imposed emergency rule and a curfew on Sunday."Down, down with Mohamed Morsi! Down, down with the state of emergency!" crowds shouted in Ismailia in defiance of the curfew. In Cairo, flames lit up the night sky where protesters set police vehicles ablaze.In Port Said, men attacked police stations after dark. A security source said some police and troops were injured. A medical source said one man was killed in clashes."The people want to bring down the regime," crowds chanted in Alexandria. "Leave means go, and don't say no!" they shouted.Volleys of teargasPropelled to the presidency in a June election by the Muslim Brotherhood, Mursi has lurched through a series of political crises and violent demonstrations while trying to shore up the economy and of prepare for a parliamentary election to cement the new democracy in a few months. The instability unnerves Western capitals, where officials worry about the direction of a key regional player that has a peace deal with Israel. The United States condemned the deadly violence and called on Egyptian leaders to make clear violence is not acceptable. In Cairo on Monday, police fired volleys of teargas at stone-throwing protesters near Tahrir Square, cauldron of the anti-Mubarak uprising. Protesters stormed into the down town Semiramis Intercontinental hotel and burned two police vehicles.A 46-year-old bystander was killed by a gunshot early on Monday, a security source said. It was not clear who fired."We want to bring down the regime and end the state that is run by the Muslim Brotherhood," said Ibrahim Eissa, a 26-year-old cook, protecting his face from teargas wafting towards him.The political unrest has been exacerbated by street violence linked to death penalties imposed on soccer supporters convicted of involvement in stadium rioting in Port Said a year ago.As part of emergency measures, a daily curfew will be imposed on the three canal cities from 9 p.m. The president announced the measures on television on Sunday: "The protection of the nation is the responsibility of everyone. We will confront any threat to its security with force and firmness within the remit of the law," Morsi said.His demeanor in the address infuriated his opponents, not least when he wagged a finger at the camera.He offered condolences to families of victims. But his invitation to Islamist allies and their opponents to hold a national dialogue was spurned by the main opposition National Salvation Front coalition. Those who attended were mostly Morsi's supporters or sympathizers.The demonstrators accuse Mubarak's successor Morsi of betraying the revolution that brought down Mubarak. Morsi and his supporters accuse the protesters of seeking to overthrow the country's first ever democratically elected leader through undemocratic means.Monday was the second anniversary of one of the bloodiest days in the revolution, which erupted on January 25, 2011 and ended Mubarak's iron rule 18 days later.The past two years have seen the Islamists win two referendums, two parliamentary elections and a presidential vote. But that legitimacy has been challenged by an opposition that accuses Morsi of imposing a new form of authoritarianism, and punctuated by repeated waves of unrest that have prevented a return to stability in the most populous Arab state.The army has already been deployed in Port Said and Suez and the government agreed a measure to let soldiers arrest civilians as part of the state of emergency.A cabinet source told Reuters any trials would be in civilian courts, but the step is likely to anger protesters who accuse Mursi of using tactics like those used by Mubarak.