The Fallujah city council chairman, a critic of al-Qaida who took the job after his three predecessors were assassinated, was killed, the latest blow in a violent internal Sunni struggle for control of an insurgent stronghold west of Baghdad. In the capital, US and Iraqi officials defended plans to build a barrier around a Sunni enclave to protect its inhabitants from surrounding Shiite areas, while residents expressed concern it would isolate the community. Sami Abdul-Amir al-Jumaili was gunned down by attackers in a passing car Saturday as he was walking outside his home in central Fallujah, 65 kilometers west of Baghdad, according to police. His assassination came a month after he raised his hand to take the dangerous job, promising to improve services and to work with the Americans to ease traffic-clogging checkpoints in the city with a population of an estimated 150,000 to 200,000. The 65-year-old Sunni sheik was the fourth city council chairman to be killed in some 14 months as insurgents target fellow Sunnis willing to cooperate with the US and its Iraqi partners. Abdul-Amir's predecessor, Abbas Ali Hussein, who was shot to death on Feb. 2. Both men were strong critics of al-Qaida in Iraq, which is battling a growing number of Sunni tribes that have turned against it in the vast Anbar province - a center for anti-US guerrillas since the uprising in Fallujah in 2004 that galvanized the insurgency. US officials say tribal leaders and even some other insurgents are increasingly repelled by the group's brutality and religious extremism. The tribes also are competing with al-Qaida for influence and control over diminishing territory in the face of US assaults. The US military confirmed the killing, and provincial officials condemned it. "He was one of the many good people of the province who worked to help the city of Fallujah rebuild and regain life," the provincial government said in a statement. "This murder was a crime against all of the citizens of Iraq. We again strongly condemn this cowardly back-stabbing act." Fellow councilmen and neighbors said Abdul-Amir had run for the office before and ignored pleas from friends not to take the job because of the dangers involved. Gunmen also broke into the home of Najim Abdullah Suod, the city council chief who preceded Hussein, killing the lawyer and his 23-year-old son on Sept. 24, 2006, while Sheik Kamal Nazal, a cleric, was gunned down as he walked to work on Feb. 7, 2006. The attack came as American officials have increasingly expressed optimism about efforts to tame Anbar, a vast desert area that borders Syria, Jordan and Saudi Arabia, as alliances have been struck with influential Sunni sheiks once arrayed against American-led forces. At least 38 people were killed or found dead elsewhere in Iraq, including another top city official, the mayor of Mussayyib who died in a roadside bombing in the city about 60 kilometers south of Baghdad. One American soldier also was killed and two were wounded by a roadside bomb southwest of Baghdad, the military said. A separate roadside bombing, in Diwaniyah about 130 kilometers south of the capital, killed a Polish soldier late Friday. Prime Minister Nouri al-Maliki, meanwhile, prepared to begin an Arab tour on Sunday that will take him to Egypt, Kuwait, United Arab Emirates and Oman, his adviser Yassin Majid said. Al-Maliki will start with a visit to Egypt, the Arab world's most-populous nation, where he will meet with President Hosni Mubarak and other senior officials, Majid said. Al-Maliki's visit comes 10 days before two conferences on Iraq in the Egyptian Red Sea resort of Sharm el-Sheik. Those will be attended by Iraq's neighbors as well as Bahrain and Egypt, and delegates from the five permanent members of the UN Security Council - the United States, Russia, China, France and Britain. The US military has said that the wall in Baghdad was 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, according to the military. A handout obtained by The Associated Press from a local dignitary in Azamiyah who spoke on condition of anonymity because of security concerns but said he was given the handout by the US military during a briefing said the wall will be 3.6 meters high, about half a meter thick and topped with coils of barbed wire. The military earlier said it would run 3 miles. Some residents and local officials in the neighborhood 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. The military insisted its aim was only to protect the area and this was one of many measures being undertaken as part of a US-Iraqi security plan to pacify the capital, which began on Feb. 14. "The intent is not to divide the city along sectarian lines," Brig. Gen. John F. Campbell, the deputy commander of American forces in Baghdad, said in a separate statement. "The intent is to provide a more secured neighborhood for people who live in selected neighborhoods. Some of the people who I've talked to have had favorable comments about it, and they want us to build some of them faster." Campbell also said several more gated communities are being erected in the Iraqi capital. He did not provide specific examples but noted that some Baghdad markets also have been encircled by concrete barriers to a degree of success.