BAGHDAD, Iraq — Iraqi police stormed a farm north of Baghdad early today and freed at least 17 people who were snatched a day earlier in a mass kidnapping of about 85 workers and family members at the end of a factory shift.

The U.S. military, meanwhile, reported that four Marines and a soldier were killed in operations south and west of Baghdad, and an explosion of sectarian and revenge killings in Mosul — Iraq's third-largest city — over the past three days claimed 19 lives.

The chief lawyer representing Saddam Hussein and his seven co-defendants said they went on a hunger strike to protest the shooting death Wednesday of a defense attorney. It was the third such killing in the 8-month-old trial.

The freed kidnap victims brought to nearly 50 the number of captives who have been either released by their captors or extricated by police. About 30 of the hostages, mainly women and children, were released shortly after they were taken captive Wednesday. It is routine in Iraq for women to take their children to work.

One kidnap victim, a Shiite Muslim, said he was set free Wednesday night after showing the kidnappers a forged ID card listing him as a Sunni. He said two hostages had been killed trying to escape. The man refused to give his name fearing retribution.

"As we were leaving the factory we were stopped by gunmen. They got on our buses and told us to put our heads down. Then they took us to a poultry farm," the man said.

"One of the gunmen told us to stand in one line and then asked the Sunnis to get out of the line. That's what I did. They asked me to prove that I am a Sunni, so I showed the forged ID and three others did the same. They released us," the man said.

A National Security Ministry official, who spoke on condition of anonymity because he was not authorized to speak to reporters, told The Associated Press that several insurgents holding the kidnap victims were captured during today's morning raid on the farm in the Mishada area, about 20 miles north of the capital.

Police operations were continuing in the area, the official said, in a bid to locate the rest of the victims who were taken at the end of the day shift at al-Nasr General Complex, a former military plant that now makes metal doors, windows and pipes.

Sectarian violence has raged in the region and kidnappings and revenge killings are common, but nothing had been reported on the scale of Wednesday's mass abduction. The al-Nasr plant is between Baghdad and Taji, a predominantly Sunni Arab area.

In the capital, where a security crackdown has been in place for nine days, insurgent and sectarian bloodletting was muted today, with no major violent incidents reported by midday.

Elsewhere, the speaker of Russian parliament's upper house said today that negotiations were being held to secure the release of four Russian Embassy staffers kidnapped June 3 in Baghdad, a news agency reported. A fifth Russian was killed when the men were captured.

Federation Council speaker Sergei Mironov said "round-the-clock" talks were being conducted to secure their release, but he did not say by whom and where, according to the RIA Novosti news agency.

The military said the four Marines were killed Tuesday in insurgency-ridden Anbar province, three of them in a roadside bombing and a fourth in a separate operation. A U.S. soldier also died Wednesday south of the capital, the military said, giving no further details.

At least 2,512 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.