A series of suicide bombings in Iraq has left at least 80 people dead and another 100 injured.
In the worst attacks, suicide bombers struck two Shia mosques in the town of Khanaqin near the Iranian border, killing at least 74 people.
The bombers blew themselves up while hundreds of worshippers were attending Friday prayers, in what is being seen as an act of sectarian provocation.
Earlier, six people were killed in two suicide car bombs in Baghdad.
The attacks outside an interior ministry building in the central Jadiriya district injured at least 40 people and brought down a block of flats.
A hotel used by foreigners may also have been targeted in the attack.
A nearby interior ministry detention centre has been at the centre of a detainee abuse scandal.
The suicide bombs in Khanaqin, in north-eastern Iraq, are the latest in a string of attacks against Shia mosques.
The BBC's Jim Muir, in Baghdad, says the attacks were intended as an act of sectarian provocation, as all the casualties must have been Shia Muslims at prayer.
"Two suicide bombers wearing explosive belts walked into the Greater and the Smaller Khanaqin mosques and blew themselves up," Diyala provincial council leader Ibrahim Hasan al-Bajalan told the AFP news agency.
The blasts in enclosed spaces, packed with worshippers, caused horrendous casualties.
Hospitals throughout the region had to take in the wounded as local facilities could not cope.
BLOODIEST VIOLENCE IN IRAQ
18 Nov 2005 - 80 dead
Multiple bombings in Baghdad and two Khanaqin mosques
14 Sept 2005 - 182 dead
Suicide car bomber targets Baghdad labourers in worst of a series of bombs
16 Aug 2005 - 90 dead
Suicide bomber detonates fuel tanker in Musayyib
28 Feb 2005 - 114 dead
Suicide car bomb hits government jobseekers in Hilla
24 June 2004 - 100 dead
Co-ordinated blasts in Mosul and four other cities
2 March 2004 - 140 dead
Suicide bombers attack Shia festival-goers in Karbala and Baghdad
1 Feb 2004 - 105 dead
Twin attacks on Kurdish parties' offices in Irbil
28 Aug 2003 - 85 dead
Car bomb at Najaf shrine kills Shia cleric Muhammad Baqr Hakim and many others
Mr Bajalan said the two mosques had been completely destroyed and he expressed fears that many more casualties may be trapped beneath the rubble.
Security forces moved into the area shortly afterwards and imposed a curfew, AFP reported.
Khanaqin is a mixed Kurdish and Shia town near the Iranian border that was severely affected by the Iran-Iraq War in the 1980s.
The town lies within a Kurdish-controlled area that has so far escaped much of the violence that has afflicted other parts of Iraq.
In Baghdad, the detainee abuse scandal was sparked five days ago, when US troops found 173 prisoners - some of whom had reportedly been tortured - in a bunker in an interior ministry building.
On Friday, UN High Commissioner for Human Rights Louise Arbour called for an international investigation into the conditions for detainees in Iraq.
Most of the detainees are believed to be Sunni Arabs - the main group involved in the insurgency.
Sunni politician Saleh Mutlaq has accused the government of holding more than 1,100 prisoners at the ministry and suggested a number of them had been tortured to death.
He also called for the alleged abuses at the detention centre to be referred to international courts.