Security officers have said that two of the bombers were disguised as women and targeted Shiites leaving the mosque following Friday prayers.
It’s the second major attack on Iraq's majority community in as many days with Iraqi President Jalal Talabani labeling it "another attempt to derail the political process and fuel a sectarian conflict."
The suicide bombers attacked the Baratha mosque in northern Baghdad. Its imam, Sheikh Jalaluddin al-Saghir, is an MP with the Shiite United Iraqi Alliance, the largest bloc in the Iraqi parliament.
The imam draws thousands of worshippers every Friday wanting to listen to his passionate sermons promoting the rights of Iraq's Shiites.
"This is a filthy war against the Shiites," Sheikh Saghir told the Dubai-based Al-Arabiya satellite channel following the attack.
Aftermath
Immediately after the attack, Iraqi authorities made a desperate plea for blood donations on state television.
The channel reported that 79 people were killed and another 164 wounded in the blasts, leaving a scene of devastation outside the mosque.
Dozens of trucks and ambulances began to ferry the victims to hospitals as soon as Iraqi and US military forces could cordon off the entire area.
Call for calm
US ambassador to Iraq Zalmay Khalilzad urged "all Iraqis to exercise restraint in the wake of this tragedy, to come together to fight terror, to continue to resist the provocation to sectarian violence."
The White House echoed Mr Khalilzad’s sentiments and strongly condemned the attacks, describing the perpetrators as having no respect for religion.
"Our thoughts and prayers are with the families of those who have lost loved ones in this attack. And we wish a speedy recovery to all of those who were injured in it," State Department spokesman Sean McCormack told reporters at a briefing.
The spokesman said the US government will be working with the Iraqi authorities to try to "prevent similar types of attack".
Meanwhile Iraq's powerful Shiite politician Abdel Aziz al-Hakim blamed the blasts on loyalists of former ruler Saddam Hussein.
"These mobs of Saddamists do not care about innocent lives and they are perpetrating genocide against Shiites," Mr Hakim said.
Further bloodshed
It’s a second day of violence against Iraq’s dominant ethnic group when on Thursday a car bombing killed 10 people in the Shiite shrine city of Najaf.
Friday’s attack has evoked memories of the bombing of a Shiite shrine in the northern town of Samarra in late February.
In the aftermath of that bombing ethnic tensions boiled over and sparked hundreds of reprisal killings exchanged between the two religious groups, raising fears of civil war.
The latest violence comes amid a political deadlock as Prime Minister Ibrahim Jaafari refuses pressure to step down.
Almost four months after its national election, Iraqi leaders have failed to come up with a working cabinet due to bitter wrangling between various parliamentary blocs.
The disputes largely revolve around ministerial posts and Mr Jaafari's candidacy, but the Prime Minister has reiterated his refusal to step aside despite increasing calls for his departure from all the political factions of Iraq.
Also on Friday the US military announced the death of three servicemen in the last 24 hours raising its military death toll since the invasion to 2,347 according to an AFP count based on Pentagon figures.
Four Iraqis were also killed in rebel attacks.