A wall U.S. troops are building around a Sunni enclave in Baghdad came under increasing criticism on Saturday, with residents calling it "collective punishment" and a local leader saying construction began without the neighborhood council's approval.

The U.S. military says the wall in Baghdad is meant to secure the minority Sunni community of Azamiyah, which "has been trapped in a spiral of sectarian violence and retaliation." The area, located on the eastern side of the Tigris River, would be completely gated, with entrances and exits manned by Iraqi soldiers, the U.S. military said earlier this week.

But some residents of the neighborhood, which is surrounded by Shiite areas, complained that they had not been consulted in advance about the barrier.

"This will make the whole district a prison. This is collective punishment on the residents of Azamiyah," said Ahmed al-Dulaimi, a 41-year-old engineer who lives in the area. "They are going to punish all of us because of a few terrorists here and there."

"We are in our fourth year of occupation and we are seeing the number of blast walls increasing day after day, suffocating the people more and more," al-Dulaimi said in an interview.

U.S. and Iraqi forces have long erected cement barriers around marketplaces and coalition bases and outposts in Baghdad and other Iraqi cities such as Ramadi in an effort to prevent attacks, including suicide car bombs. But the Azamiyah project appears to be the biggest effort ever to use a lengthy wall in Baghdad to break contact, and violence, between Sunnis and Shiites.

The U.S. strategy for stabilizing Iraq now involves persuading Iraqis to live in peace and support their democratically elected government and launching a security plan in the capital that calls for 28,000 additional American troops and thousands of Iraqi soldiers.

On Saturday, one American soldier was killed and two were wounded by a roadside bomb southwest of Baghdad, the military said. A separate roadside bombing, in Diwaniyah about 80 miles south of the capital, killed a Polish soldier late Friday.

Khalid Ibrahim, 45, said the Americans were working hard to divide Baghdad's neighborhoods — something he said he wasn't sure was a good thing.

"This is good if it is temporary, to help the area with security problems. But if this wall stays for the long term, it will be a catastrophe for the residents and will restrict our movements," said Ibrahim, an Azamiyah resident who works at the Interior Ministry.

The U.S. military says it began building the barrier April 10. AP Television News footage from the site on Saturday showed small concrete blocks, piles of dirt and coils of barbed wire on a main street. Eventually, the military said, the wall will be three miles long and include sections as tall as 12 feet.

Community leaders said Saturday that construction began before they had approved an American proposal for the wall.

"A few days ago, we met with the U.S. army unit in charge of Azamiyah and it asked us, as a local council, to sign a document to build a wall to reduce killing and attacks against Iraqi and U.S. forces," said Dawood al-Azami, the acting head of the Azamiyah council.

"I told the soldiers that I would not sign it unless I could talk to residents first. We told residents at Friday prayers, but our local council hasn't signed onto the project yet, and construction is already under way."

Asked about the Azamiyah wall, Interior Ministry spokesman Brig. Abdul-Karim Khalaf said there would be "some limitations on more than one neighborhood inside Baghdad."

"There will be no isolation of any neighborhood. There will be limitations on the movement of people through specific routes, so that terrorists cannot avoid being searched," he said.

In other violence Saturday, two bullet-riddled dead bodies were discovered in Musayyib, about 40 miles south of Baghdad, police said. One of the bodies was found floating in the Euphrates River, and the other was discovered in a deserted area. Both victims had their hands and legs bound, and showed signs of torture, police said.

A bomb left on a bus exploded in Baghdad's Sadr City neighborhood, killing at least three people and gutting the vehicle, police said.

Gunmen stormed a house in Kirkuk, 180 miles north of Baghdad, killing a mother, father and their two teenage daughters, police said. The victims were Kurds who had received death threats from militants, witnesses said.

In other violence Saturday, a roadside bomb killed the mayor of Musayyib, about 40 miles south of Baghdad, police said. One of his bodyguards was also killed, and four others were wounded, they said.

Australian Defense Minister Brendan Nelson paid an unannounced visit to Iraq and met with Prime Minister Nouri al-Maliki to discuss the coalition's efforts to improve security in cities such as Baghdad, the government said.

Australia has about 1,400 troops in and around the country.

Al-Maliki and Nelson met at the prime minister's office in the capital's heavily fortified Green Zone, and al-Maliki "underlined that Iraqi forces are unified in battling terrorists and outlaws, and are now fighting shoulder to shoulder throughout Iraq," especially in hard-hit areas such as Baghdad and the provinces of Anbar, west of the capital, and Diyala, to the northeast, a government statement said.