BAGHDAD, Iraq — The merchants were silent, their shops closed. A hush had fallen on the Jamiyat Shurta market. Earlier that morning, three bakers had been shot — silently assassinated as they prepared khubuz, a popular pancakelike bread.

A few hours later, two gunmen crept up on a fishmonger at another market nearby, felling him with bullets before disappearing into the crowd.

Around the corner, assailants gunned down a bicycle dealer and a university teacher in separate attacks this week.

All the men were Shiites, living or working in the Baghdad neighborhood of Dora.

On the streets of the capital, posters proclaim: "The constitution: Unity is from it, and hope is in it."

But, as Iraqis head to the polls to vote on a new constitution Oct. 15, hope and unity are in short supply as gunmen redraw the map of this age-old city in blood.

An apparent campaign of sectarian killings is deepening the chasm between the country's Shiite majority and Sunni Arab minority.

A wave of bombings has killed at least 111 people in the past two days in predominantly Shiite areas. When a car bomb exploded near a vegetable market in Hilla south of Baghdad yesterday, at least eight people died and 41 were wounded, according to police.

In Balad, where three successive bombs struck merchants and shoppers Thursday, doctors worked nonstop to save the wounded, who numbered in the hundreds; by yesterday, the death toll from that attack reached 103. Many residents say their town was targeted because they are Shiites.

But Sunnis, too, are complaining of abuses, including torture and assassinations, alleging that rogue Iraqi security forces, or people posing as them, routinely abduct and execute Sunni men. In the past few months, bodies have turned up in the Tigris River, a garbage dump, an abandoned truck and, this week, near a rail yard.

Yesterday, in the capital's Umm Qura Mosque, Sheik Ahmed Abdel Ghafour called on Sunnis to defend themselves against suspicious Iraqi security troops. "It's better for the Iraqi to be killed in his house than tortured, killed and thrown in the streets," he said.

Baghdad has become a microcosm of Iraq, with sectarian lines hardening. Residents are being forced from neighborhoods in and near the capital.

On Monday, insurgents dragged five Shiite teachers and their driver into a classroom in the village of Muelha, 30 miles south of Baghdad, and shot them to death.

Tuesday night, men clad in police uniforms came for seven Sunnis in the Hurriya neighborhood. The following day, police discovered their bodies dumped near a railway line in Shula, a northwestern Baghdad district. The men had been blindfolded, handcuffed and shot execution-style.

In Dora, which stretches over 30 square miles, a systematic campaign of intimidation is forcing Shiites to flee, leaving rows of empty houses and changing the fabric of this once-diverse neighborhood on the southern rim of the capital, authorities say. At least 150 families have left within the past year.

When U.S. and Iraqi security forces began a crackdown in other Baghdad neighborhoods this year, insurgents simply slipped into Dora, police said.

"A good number of Saddam's followers used to live in these places, and once the insurgents ... joined them, Dora started to witness such incidents," said Dora police Capt. Khudayir Muhammad.

What makes the neighborhood attractive to insurgents, police say, is its size, proximity to central Baghdad, a network of back roads leading south to the Sunni Triangle and an abundance of farms that can be used as rebel hide-outs.

In Baghdad, meanwhile, Iraqi troops at a checkpoint yesterday captured a woman strapped with explosives under her clothes who was headed for a flea market to carry out a suicide bombing, said army Gen. Jalil Khalaf.

Information from The Associated Press is included in this report.