The US military has warned that the Iraqi government is unprepared to deal with a mass return of refugees to Baghdad as they face new security concerns despite declining violence. Thousands of Iraqis have flowed back to their homeland in recent weeks, mainly from Syria, encouraged by a reduction in overall attacks along with a government promise of money and free transportation. But many of those returning face an uncertain future with houses occupied by members of the rival Islamic sect or burned to the ground during the violence that has changed the religious character of entire neighborhoods and left the capital a maze of concrete walls. Many formerly mixed neighborhoods also have become entirely Shi'ite or Sunni. "All these guys coming back are probably going to find somebody else living in their house," said Col. Bill Rapp, a senior aide to the top US commander in Iraq. "This is a major concern. The government of Iraq doesn't have a policy yet. We have been asking, pleading with the government of Iraq to come up with a policy." The concerns echoed a warning by the chief U.N. humanitarian organization that it is too early to promote returns as the security situation in the country remains volatile. Starved for good news, the Shi'ite-led government has pressed ahead with efforts to draw Iraqis home, pointing to the returnees as proof that Iraq was finally on the road to stability. About 20 buses carrying hundreds of Iraqi refugees arrived in Baghdad from Syria late Wednesday, the first results of a government-funded effort aimed at exploiting growing the public confidence. Amir Safaa, a 22-year-old Sunni cell phone repairman, fled with his family about a year ago as sectarian violence was tearing his southwestern neighborhood of Sadiyah apart. He had hoped to return last week but was told his house had been occupied by a Sunni army officer's family. Safaa said his family was in negotiations to get their house back. "We hope that we will be able to return to our house, despite some warnings by friends that the security situation is not perfect," he said. "Rents are very high in Syria. Moreover, Syrian authorities kept tightening restrictions on work." US military officials said the situation raised alarm bells as the government had not issued word on how it planned to deal with disputes arising from the returns as well as other related issues. Rapp said Wednesday during a briefing for reporters on measuring military trends that one option was building new housing for those who return to find their homes gone. Satar Nawrouz, the spokesman for Iraq's Ministry of Migration and Displacement, said suggested policies for helping to reintegrate refugees into their communities had been presented to the government. "One of these proposals is setting regulations for easing the process of re-employing the returnees in governmental departments and accepting their children in Iraq schools," Nawrouz said, without elaborating. National Security Minister Sherwan al-Waili, who met the convoy on Wednesday, also said Prime Minister Nouri al-Maliki would give each returning family 1 million Iraqi dinars to get started rebuilding their lives. No comprehensive numbers have been released on the numbers of Iraqis returning home sometimes years after fleeing as retaliatory violence spiraled in Baghdad after the February 2006 bombing of a revered Shi'ite shrine in the northern city of Samarra. The UN High Commissioner for Refugees has estimated that "around 600 Iraqis have left Syria each day this week, although not all are refugees." Officials in Iraq and Syria have said more than 46,000 refugees returned in October and the flow has continued this month. Many Iraqis have headed back on their own from Syria and elsewhere as extremist attacks have fallen sharply in Baghdad and other areas. The move also has been prompted by tighter visa rules in Syria and poor job opportunities that have left many of the refugees impoverished. The military is largely taking an advisory role on the issue but is pressing the government to establish a system for adjudicating property claims and to avoid forced evictions. "We're working with the government of Iraq so they can be prepared," said Col. Cheryl Smart, who monitors data on displaced Iraqis for the military. Rapp said one possible solution was new housing construction but he voiced fear that reintegration would be a lengthy process that could threaten the recent security gains. "Whether they will remix is probably a multiyear, decade kind of issue," he said, cautioning that mass returns "will create tensions in that system, and we are concerned about it." UNHCR estimated that 800 Iraqis crossed the border from Syria en route to Baghdad in Wednesday's heavily secured convoy. The agency said most of the refugees were going back to Iraq because they had run out of money, not only because the security situation appeared to be improving. "Figures compiled by UNHCR suggest that only 14 percent of Iraqi refugees are returning because of improved security conditions," the agency said on its Web site. "Around 70 percent say they are leaving because of tougher visa regulations and because they are not allowed to work and can no longer afford to stay in Syria."