Rock-throwing protesters fought riot police through clouds of teargas to within meters of Egypt's Interior Ministry on a second day of clashes triggered by the deaths of 74 people in the country's worst soccer disaster.Three demonstrators and an army officer were killed in Cairo and an additional four were killed in the city of Suez, according to Al Jazeera. In addition, over 17,000 people were wounded. Police used live rounds to hold back crowds trying to break into a police station and fought in front of the state security headquarters, witnesses and the ambulance authority said.US Senate threatens Egypt aidAlso Friday, a leading US senator warned Egypt's military-led government that "the days of blank checks are over" as an Egyptian army team huddled with State Department officials to discuss the future of $1.3 billion in annual US military aid.Senator Patrick Leahy, a Democrat who chairs the Senate subcommittee in charge of foreign aid, issued a blistering attack on Egypt's crackdown on local and US-funded pro-democracy groups and warned that Congress could block future aid unless changes are made."We want to send a clear message to the Egyptian military that the days of blank checks are over. We value the relationship and will provide substantial amounts of aid, but not unconditionally," Leahy said in his statement.Leahy joined a growing number of US. lawmakers from both political parties who have expressed outrage over the swoop on non-governmental organizations, which has seen a number of US staffers barred from leaving Egypt.In two joint letters released on Friday, more than 40 US lawmakers warned US Secretary of State Hillary Clinton, Defense Secretary Leon Panetta and Field Marshal Mohamed Hussein Tantawi, the head of Egypt's ruling military council, that US aid to the Egyptian military hung in the balance.Jpost.com staff contributed to this report.Most of those killed in the Port Said football stadium on Wednesday night were crushed in a stampede and the government declared three days of mourning, but protesters hold the military-led authorities responsible.It was country's deadliest incident since an uprising ousted Hosni Mubarak almost a year ago and it gave fresh impetus to regular street protests against Egypt's ruling generals."We will stay until we get our rights. Did you see what happened in Port Said?" said 22-year-old Abu Hanafy, who arrived from work on Thursday evening and decided to join the protest.The ministry in Cairo, an object of hatred for football fans who say lax policing was to blame for the stadium disaster, has been hemmed in by the street battles since Thursday.Thousands were still battling riot police there and more protesters were expected to gather in the center of the capital for a "Friday of Anger" declared by 28 youth activist groups and political parties.Rocks thrown by protesters were strewn across streets that two months ago witnessed violent clashes between police and activists who see the Interior Ministry as an unreformed vestige of Mubarak's rule.Hardcore football fans known as "ultras," who often clash with the police and were at the forefront of the uprising against Mubarak, vowed to continue their protests.In Suez, witnesses said fighting broke out at a local police station in the early hours of Friday. "We received two corpses of protesters shot dead by live ammunition," said a doctor at a morgue.Many shops in Suez were wrecked and the facade of the Suez Canal Bank was destroyed.Police cordoned off the Suez state security headquarters and a Justice Ministry compound with razor wire and seven burned-out vehicles lay nearby. Roads were strewn with glass.The soccer stadium deaths have heaped new criticism on the military council that has governed Egypt since Mubarak stepped down. Critics regard the generals as part of his administration and an obstacle to change.The army leadership, in turn, has presented itself as the guardian of the "January 25 revolution" and promised to hand power to an elected president by the end of June.