Egyptians incensed by the deaths of 74 people in soccer violence clashed with security forces during protests against the army-led government for failing to prevent the deadliest incident since the overthrow of Hosni Mubarak.
Security forces fired tear gas at demonstrators near the headquarters of the Interior Ministry in Cairo, prompting hundreds to flee.
State media reported scuffles between members of the security forces and demonstrators and said 628 people were injured, mostly from tear gas inhalation.
The Interior Ministry said in a statement that security forces were protecting the building after protesters cut the wire barricades and climbed over concrete walls in an attempt to reach the building.
As tear gas canisters flew, witnesses saw unconscious people being ferried away from the area on motorbikes and ambulances raced to the scene.
The incident at the stadium in Port Said last night was Egypt's worst ever soccer disaster. Bodies were unloaded from a train at Cairo's main train station, covered by blankets.
At least 1,000 people were injured in the violence when soccer fans invaded the pitch after local team al-Masry beat Cairo-based Al Ahli, the most successful club in Africa.
Hundreds of al-Masry supporters surged across the pitch to the visitors' end and panicked Ahli fans dashed for the exit. But the steel doors were bolted shut and dozens were crushed to death in the stampede, witnesses said.
The incident has triggered fresh criticism of the ruling military council, which has pledged to hand power to an elected president by the end of June. The head of the council said any attempts to cause instability would not succeed.
In the newly-elected parliament, MPs including the Islamists who control some 70% of the chamber demanded the government be held to account during an emergency session attended by Prime Minister Kamal al-Ganzouri.
Addressing angry lawmakers, Ganzouri said senior security chiefs in Port Said and the city's governor had been suspended and the soccer federation's board had been sacked. But he disappointed those seeking tougher steps, such as firing the interior minister.
Some MPs echoed the suspicion of many Egyptians that the incident was the work of remnants of the Mubarak administration trying to derail reform.
The MPs voted to launch an investigation into what happened and lodge a formal complaint with the military against Interior Minister Mohamed Ibrahim, accusing him of negligence.
The Supreme Council of the Armed Forces, headed by Mubarak's long-time defence minister, vowed to track down the culprits and declared three days of national mourning.
It did little to assuage the anger of fans, who, like many Egyptians, are furious that Egypt is still plagued by lawlessness and violence almost a year after Mubarak was driven out.