BEIRUT: Iraqi Shiite forces and Syria accused Monday the United States of hitting their troops inside Syria with an airstrike, a charge the US denied but which ratcheted up tensions in the area nonetheless. Iraq’s Iran-backed Popular Mobilization Forces, the units’ umbrella organization, said in a statement that US aircraft fired two missiles that hit late Sunday night a group of its fighters who were deployed along the Iraq-Syria border to prevent Daesh from penetrating the Iraqi border. The statement said the attack left 22 fighters dead and 12 wounded, adding that Iraqi and Syrian authorities were aware of their deployment. “We demand that the American side issues a clarification for what happened,” the Iraqi group said. Syrian state media had reported earlier that the airstrike against pro-government forces in the far east of the country had caused casualties, while Iraqi officials said it had killed at least 25 Shiite paramilitaries and was just across the border from its own territory. The Syrian state TV report blamed the attack on the US-led coalition battling Daesh, saying it occurred around midnight in the village of Al-Hari, to the southeast of the border town of Boukamal. But a coalition spokesman denied that, saying it had not carried out any strikes in the area. In Baghdad, Iraqi officials said state-sanctioned Shiite paramilitaries came under attack south of the town of Qaim, just across the border from Boukamal. They said 25 fighters were killed, three are missing and about 30 were wounded. But did not give details into how the attack was carried out, saying only that investigations were under way, speaking on condition of anonymity because they were not authorized to speak to the media. The officials said the dead were mostly members of Iraq’s Hezbollah Brigades, which have been active in Syria’s civil war fighting alongside government forces. Also killed were some members of the Sayyed Al-Shuhada Battalions, they said. In Syria, an official with the so-called “Axis of Resistance” led by Iran, which includes Iran, Syria, Hezbollah and other groups fighting alongside President Bashar Assad’s forces, told The Associated Press that the attack on Syrian and Iraqi positions on both sides of the border had been carried out by American drone aircraft. The official, who spoke on condition of anonymity because of the secrecy of information, added that the troops had been part of a push against IS extremists in the area. US military spokesman Col. Sean Ryan said the coalition was looking into the reports. “We are aware of the strike near Boukamal, however there have been no strikes by US or coalition forces in that area,” he said. “We’re looking into who that could possibly be, but it wasn’t the US or the coalition.” The Britain-based Syrian Observatory for Human Rights, a war monitor, said the airstrike killed 52 foreign fighters allied with the Syrian government, mostly Iraqis. Shiite militias fighting alongside government forces in Syria include large numbers of Iraqi, Lebanese and Afghan fighters. Last week, Daesh launched a major offensive against Boukamal, reaching the outskirts of the town before being pushed back by government forces. The loss of the town would deal a major blow to Iran-backed forces on both sides of the border, who have established a corridor through eastern Syria to link Iran to the Mediterranean Sea. Syrian and Iraqi forces have driven Deash from virtually all the territory it once held in both countries, but the militants still control some remote areas along the border.