BAGHDAD — Gunmen trying to pass themselves off as U.S. and Iraqi soldiers raided a Sunni village outside Baghdad and killed at least 24 people in an execution-style attack, apparently targeting a Sunni group that revolted against al-Qaida in Iraq, authorities and witnesses said Saturday.

The bloodshed late Friday comes amid increasing concerns that insurgents will take advantage of Iraq’s political turmoil to further destabilize the country, nearly a month after parliamentary elections failed to give any candidate a decisive win. Many fear a drawn-out political debate could spill over into violence and complicate American efforts to speed up troop withdrawals in the coming months.

Details remained sketchy, but police said gunmen traveling in at least four cars raided three homes in Hawr Rijab, killing 19 men and five women after binding them in handcuffs. Some of the victims, police said, were marched onto the roofs of their homes and slain there.

Some had broken arms and legs, indicating they had been tortured before they were shot, police said. One witness said many were so badly brutalized that they were “beyond recognition.”

At least seven people were found alive, bound with handcuffs, authorities said.

The killings were reminiscent of those that plagued Iraq at the height of the sectarian bloodshed of 2006 and 2007, when men, sometimes dressed in police or army uniforms, snatched people from their houses at night before killing them and dumping the bodies.

Similar violence still plagues the country, but it has ebbed sharply.

In November, gunmen in Iraqi army uniforms abducted and killed 13 people in al-Saadan near the town of Abu Ghraib on Baghdad’s western outskirts.

One survivor of Friday’s attack said the gunmen gained entry to her home by speaking English and convincing her mother they were U.S. soldiers on a patrol.

“My mother thought they were Americans who came to search the house, that’s why she opened the door,” said the woman, who ran to another room after seeing the attackers. Her mother and two brothers were killed.

“I heard four gunshots,” the woman said. “It was all over in a second.”

The woman did not give her name, but she agreed to allow an AP Television News crew to tour her home, where blood was spattered on the white kitchen cabinets and pooling on the floors.

A senior Iraqi army official who arrived at the scene Friday evening said witnesses told him the gunmen were wearing uniforms that resembled those of the American military, and that they tricked the residents by saying they were coming to ask them how they were faring in their village.

The official spoke on condition of anonymity because he was not authorized to release details publicly.

The U.S. embassy in Baghdad condemned the attack and urged Iraqi authorities to conduct a thorough investigation.

The American presence on Iraqi streets has been drastically reduced since the U.S. withdrew from cities last summer, the first step toward a full withdrawal by the end of next year.

U.S. raids of people’s homes were common in the years that followed the 2003 invasion that ousted Saddam Hussein, but the Americans have turned over authority to the Iraqis and no longer have free rein.

Many of the dead were members of a local Awakening Council — the Sunni fighters who changed the course of the war when they revolted against al-Qaida in Iraq and joined the Americans in late 2006 and 2007, said Mustafa Kamel, a Sahwa leader south of Baghdad.