At least 38 people have been killed in fresh violence in Baghdad, police say.
The bullet-riddled bodies of 14 men were recovered together in the Shaab district of the Iraqi capital.
Four Shia students were pulled from a vehicle and shot dead late on Tuesday, and about 20 bodies were found after a number of other attacks.
In nearby Falluja, at least five people were killed when a suicide bomber struck on Wednesday morning as crowds of men gathered to join the police.
Sectarian violence has soared since the bombing of a revered Shia shrine in February. The US military estimates attacks on civilians have doubled.
The identities and sectarian affiliations of the 14 bodies discovered in Shaab are as yet unknown.
But they were young men aged between 20 and 30, they were blindfolded, bound and showed signs of torture - the hallmarks, according to the BBC's Jim Muir in Baghdad, of a sectarian attack.
Cycle of killings
Our correspondent says that many of the victims of massacres of this type have been Sunnis, some of them picked up by death squads which the Shia-controlled interior ministry is accused of allowing to operate under its cover.
But he says it is certainly not a one-way process - most of the victims of the Sunni-based insurgency have been Shia.
The four students appear to have been stopped in their car by gunmen who set up a fake checkpoint.
According to the Associated Press, the five killed in the attack in the restive city of Falluja were three applicants for jobs with the police, and two policemen.
Breaking the cycle of sectarian revenge killings will be one of the first and biggest challenges facing the new Iraqi government which is currently being put together, our correspondent says.
There is much debate over who should be in charge of the interior and defence ministries. It looks unlikely that they will again be put in the hands of people connected to the big factions and militias, he says.