Police in Baghdad have recovered at least 49 bodies from the streets of the capital in the past 24 hours, an interior ministry official has said.
Sectarian violence is claiming dozens of victims in Baghdad daily
A spokesman said most of the victims had been shot in the head, and showed signs of having been tortured.
The latest discoveries take the number of bodies found in Baghdad in the past three days to more than 100.
Correspondents say some of those killed were probably the victims of attacks by sectarian militias.
Others could have been targeted by criminal gangs hoping to obtain ransoms.
Also on Friday, US military officials said insurgents have killed seven US servicemen and wounded dozens more in the past 48 hours across Iraq.
So far in September, 25 US soldiers have been killed,
Separately, Iraqi security forces in Basra are expected to begin a large-scale operation against sectarian militias within the next few days.
Iraq's second city has not suffered as much violence as Baghdad, but local security officials say they are determined to end the activities of death squads and mortar attacks on residential areas.
James Shaw, a BBC correspondent in Iraq, says the vast majority of the population in Basra is Shia, which means there is less activity by Sunni insurgents than in the capital. But those Sunnis who do live in the city have been targeted by Shia death squads.
General Ali Hammadi, in charge of the city's security committee, said that thousands of Iraqi troops would be used in a series of operations over the next few months to try to uproot the militias and other criminal gangs.
They will be backed by British forces based near the city.
The task will be made more complicated by the fact that there is thought to be widespread infiltration of the security forces by militia members.