Iraqi Shiites fight for Syrian government BAGHDAD - The Iraqi fighters in the video shoulder assault rifles and rocket-propelled grenades as they walk down a highway lined with cypress trees. Grinning, some hold up cellphones and camcorders to capture the moment - the aftermath of a victorious battle to secure the Aleppo airport from Syrian rebels who had attempted to take it. "You are the sons of Iraq and the sons of Islam!" shouts one of their commanders. The men cheer. Weeks later in Baghdad, Abu Sajad, the nom de guerre of an Iraqi militia commander who appears in the video, proudly displayed it as proof that Iraqi Shiites are playing a critical role in supporting the regime of Syrian President Bashar al-Assad in what has become an increasingly sectarian and regional war. It was impossible to verify the location and circumstances of the video. Until recently, the involvement of Iraqi Shiites in Syria's war was cloaked in secrecy here in Iraq, whose Shiite-led government has denied involvement in the conflict. But recent interviews with militants, analysts, Arab government officials and residents of Shiite cities across Iraq reveal a trend that is growing increasingly open as Iraqi fighters come to view their participation as part of a regional struggle to defeat al-Qaeda and what they say is a broad effort by the region's dominant Sunnis to wipe out Shiites. At the center of the Shiite mobilization is Iran, which analysts and intelligence officials say is seeking to preserve its regional influence by funding and supplying an expanding Shiite network of armed support for the Syrian government, which is dominated by Assad's Alawite sect, an offshoot of Shiite Islam. In addition to combatants from Iranian security forces and the Lebanese militia Hezbollah, pro-Assad proxy fighters also include Iraqis drawn largely from militant groups known to be backed by Iran. The role of Iraqi Shiite fighters in Syria raises questions about the possible complicity of the Iraqi government, which U.S. officials have recently criticized for allowing Iran to use its airspace for flights that allegedly transport weapons, troops and supplies to the Assad government. Iraqi officials say they have agreed to U.S. requests for inspections of the Iranian overflights. Eight recent random inspections have found "nothing illegal," said Kareem Nouri, a Transportation Ministry spokesman. "We support neither the opposition nor the regime in Syria, and we will not make Iraq a part of the fight in Syria," he said. But Iraqi officials have warned repeatedly that Assad's fall would spell disaster for Iraq, and Iraqi Prime Minister Nouri al-Maliki told the Associated Press in February that a rebel victory in Syria would revive Iraq's sectarian war. In an interview, Sami al-Askari, a Shiite lawmaker close to Maliki, said the government "turns a blind eye" to the flow of Shiite fighters to Syria, as it does in the case of Sunnis who help Syrian rebels. Shiite militia leaders and analysts say it is unclear how many Iraqi Shiites have gone to fight in Syria, but Abu Sajad put the number at about 200 and said the ranks were quickly growing. He said Shiite fighters had been particularly motivated by an April statement by al-Qaeda leader Ayman al-Zawahiri, who glorified the Syrian opposition in what he depicted as its fight against Assad and Iran, and by the Syrian Islamist rebel group Jabhat al-Nusra's recent pledge of fealty to al-Qaeda.