Three days of national mourning have been declared by the authorities in Egypt after at least 74 people died in clashes between rival football fans in the city of Port Said. Hundreds more were injured as fans invaded the pitch after a match between top-tier clubs al-Masry and al-Ahly. Emergency meetings of the cabinet and parliament have been called. Protest marches are being planned for Thursday against the police's inability to contain the violence. One al-Ahly fan told the BBC that fans will march from the al-Ahly's club in Cairo to the Interior Ministry. "People are angry at the regime more than anything else... People are really angry, you could see the rage in their eyes," Mohammed Abdel Hamid said. Hundreds gathered at Cairo's main railway station to receive the injured and the first bodies arriving from Port Said, with some chanting slogans against military rule. "Everyone was beating us. They were beating us from inside and outside, with fireworks, stones, metal bars, and some had knives, I swear," one fan told a private TV station. Army units were deployed in Port Said and joined police patrols around morgues and hospitals, but most streets had no police presence. Field Marshal Hussein Tantawi, the head of Egypt's ruling army council, went to an airbase near Cairo to meet al-Ahly players who were flown back from Port Said on a military aircraft. "This will not bring Egypt down... These incidents happen anywhere in the world. We will not let those behind it go," he said, according to the Associated Press news agency. It is the biggest disaster in the country's football history, said the Egyptian deputy health minister. "This is unfortunate and deeply saddening," Hesham Sheiha told state television, adding that many people died in a stampede as people tried to leave the stadium. Some of the dead were security officers, AP quoted a morgue official as saying. Tense atmosphere The BBC's Jon Leyne in Cairo says it appears some fans had taken knives into the stadium. Our correspondent says the lack of the usual level of security in the stadium might have contributed to the clashes. Police in Egypt have been keeping a much lower profile since last year's popular protests that ousted President Hosni Mubarak from power. Egyptian fans are notoriously violent, says our correspondent, particularly supporters of al-Ahly known as the Ultras. They have been heavily implicated in confronting the police during recent political protests, our correspondent adds. There is speculation that the security forces may have had an interest in taking on al-Ahly supporters. Wednesday's violence broke out at the end of the match, which, unusually, Port Said club al-Masry won 3-1. Witnesses said the atmosphere had been tense throughout the match - since an al-Ahly fan raised a banner insulting supporters of the home team. As the match ended, their fans flooded onto the pitch attacking al-Ahly players and fans. A small group of riot police tried to protect the players, but were overwhelmed. Part of the stadium was set on fire.