By Middle East correspondent Hayden Cooper, wires
Photo: Deadly clashes broke out in the capital and several other cities between pro-Morsi supporters and security forces. (REUTERS: Al Youm Al Saabi Newspaper)
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Clashes have broken out in the Egyptian capital Cairo involving supporters and opponents of the Muslim Brotherhood after a wave of bomb attacks targeting police.
At least six people died in the explosions and 76 more were wounded, officials said.
In the largest attack, a car bomb exploded at a security compound in the city's centre early in the morning and killed at least four people, including three policemen, security sources said.
Officials said the blast was the work of a suicide bomber, but local television footage showed a man getting out of a van minutes before it exploded.
State television quoted witnesses as saying gunmen on motorcycles opened fire on buildings after the explosion.
Three smaller bombs were also detonated, including one in the Dokki district that killed one person and another near a cinema on the outskirts of Cairo, which also led to one fatality.
A militant group called Ansar Beit al-Maqdis, or the Champions of Jerusalem, claimed responsibility for the attacks.
Deadly clashes and condemnation
Thousands of Muslim Brotherhood supporters clashed with security forces in Cairo following the bomb attacks, with police using tear gas to quell the unrest.
The violence comes on the eve of the third anniversary of the uprising that toppled autocrat Hosni Mubarak and raises fears that an Islamist insurgency is gaining pace in Egypt.
The 2011 revolt raised hopes of a stable democracy in the Arab world's biggest nation.
Instead, relentless political turmoil has hit investment and tourism hard in Egypt.
Members of the Muslim Brotherhood are today planning more protests and some government ministers have called for regime supporters to take to the streets as well.
The army-backed government has condemned the bloodshed.
Since coming into power, it has effectively removed the Brotherhood from politics and many Egyptians turned against it after Morsi's troubled one-year rule.
In a statement, prime minister Hazem el-Beblawi said it was an attempt by "terrorist forces" to derail the army-backed government's political road map, which is meant to lead to free and fair elections.
The office of president Adly Mansour also released a statement, saying it would "avenge the deaths of the martyrs" who died at the Security Directorate and severely punish the perpetrators.
Later in the day, a military helicopter flew back and forth over central Cairo, underscoring concerns that another attack could happen at any time.
In Washington, the White House condemned the bombings and urged all sides to avoid violence.
"These crimes should be investigated fully and the perpetrators should be brought to justice," spokesman Jay Carney said.
Photo: Supporters of Egypt's military government wave flags in downtown Cairo. Thousands of Muslim Brotherhood supporters also took to the streets. (Reuters: Mohamed Abd El Ghany)
'Traitors and dogs'
The police headquarters assault will likely encourage the state to crack down harder on the Brotherhood, which it accuses of terrorist acts.
The group says it is a peaceful movement.
Human rights groups accuse security forces of widespread human rights abuses in their crackdown on the Brotherhood, but the group has little sympathy on the street.
The mood was tense at the Cairo Security Directorate.
"Traitors and dogs!" yelled onlookers, an apparent reference to the assailants.
People also chanted anti-Brotherhood slogans.
"The people want the execution of the Brotherhood. Execution for Morsi," they yelled.
One woman, Wafaa Ahmed, was crying outside the Cairo Security Directorate.
"These people have no sense of loyalty to the nation," she said.
"This is terrorism, they want to get back at us because we finished them off."
ABC/wires
