Suspected Shia Muslim militants have destroyed three Sunni mosques near the Iraqi capital, a day after a repeat attack on a major Shia pilgrimage site.
Samarra's dome was destroyed in 2006, its minarets 16 months later
The overnight attacks bring to six the number of Sunni mosques targeted since suspected Sunni militants toppled the two minarets of the Samarra shrine.
Curfews appear to have prevented the same level of violence seen after a similar attack on the mosque last year.
Then militants blew up Samarra's dome, triggering massive reprisals.
The BBC's Andrew North says that attack on 22 February 2006 brought Iraq to the brink of civil war.
An official in the prime minister's office said the curfew in Baghdad would be lifted on Saturday.
But the threat of major sectarian bloodshed remains, our correspondent says, with many Sunni communities still fearing retribution from Shia death squads.
Three Sunni mosques near Baghdad were attacked hours after the Samarra attack, although one was only partially destroyed.
Unidentified men returned to the Hutin mosque in Iskandariya, south of the capital, in the early hours of Thursday and planted bombs, causing a huge explosion, police said.
In Mahaweel, also south of Baghdad, gunmen opened fire on the Bashir mosque at dawn, forced guards to leave and set fire to the building, police said.
Reports say at least one other Sunni mosque was attacked in Iskandariya overnight, a day after the town's Grand mosque and Abdullah Jabburi mosque were destroyed.
The Khudair al-Janabi mosque in Baghdad's Bayaa neighbourhood was also bombed, police and local residents said.
The head of the US forces in Iraq described the bombing of the al-Askari shrine, one of Shia Islam's holiest sites, as a serious blow.
But, speaking on American television, General David Petraeus also said he hoped it would help to unite Iraqi leaders.
Earlier, religious and political leaders in Iraq called for restraint after two minarets were destroyed at the shrine.
The party of the Iraqi prime minister, Nouri al-Maliki, blamed al-Qaeda for the attack.
The political bloc loyal to the radical Shia cleric, Moqtada Sadr, suspended its participation in parliament in protest at the attack.