CAIRO — Thousands of Egyptians Sunday closed down government offices and factories in the Suez Canal city of Port Said, demanding justice for dozens of people killed in clashes with police, witnesses said. Demonstrators also shut down schools and banks and blocked a main railway route, but their protests did not impact traffic through the strategic Suez Canal, a canal official said. The marchers were demanding justice for at least 40 protesters killed in clashes with police in late January after a court sentenced 21 soccer fans from the city to death over a deadly football riot last year. In February 2012, 74 people, mostly supporters of the Cairo Al-Ahly club, were killed in a football riot in Port Said. Home fans were held to blame, with Al-Ahly supporters pledging civil disobedience in Cairo if the court acquitted the Port Said residents. Witnesses said around 3,000 people took part in the protest. “With our lives, with our blood, we will sacrifice ourselves to you martyrs: Either we avenge you or we die like you!” they chanted. “The disobedience will last for one day and could continue if the protesters' calls for the death sentence for the killers of martyrs are not granted,” said Ahmad Mutwalli, a political activist. The protesters also disrupted train services. But Gen. Ahmed Najeeb, head of the General Authority of Port Said, said the protest had not affected shipping activity at the Mediterranean port. ‘Army will avoid politics' Egypt's armed forces, for decades at the center of power, will avoid involvement in politics but could have a role if things became “complicated”, the chief of staff has said. It also expects rival political groups to solve disputes by dialogue, Maj. Gen. Sedki Sobhi said. The military ran Egypt for six decades from the end of the colonial era and through an interim period after the overthrow of former air force chief and president Hosni Mubarak two years ago. Speaking to Reuters at an industry event in Abu Dhabi, said that in a week or 15 days some kind of national dialogue would take shape between the ruling Muslim Brotherhood and oppositioin groups. The army would not back any political party, he said. “We are not political, we don't want to participate in the political situation because we suffered a lot because of this,” he said. — Agencies