US forces were targeted in three attacks in Iraq on Thursday but suffered no casualties, security sources have said, in the most geographically widespread series of strikes on US assets in a single day since the Israel-Hamas conflict started. Spokespeople for the US embassy in Baghdad and US-led international forces stationed in Iraq did not immediately respond to requests for comment. A joint patrol of US forces and the Iraqi counter-terrorism service was targeted by an explosive device near the northern city of Mosul, causing damage to a vehicle but no casualties, two security sources said. Armed drones also targeted the al-Harir airbase in Erbil and the Ain al-Asad airbase west of Baghdad, both of which house US and international forces. The drones were downed by air defences and caused no casualties, security sources said. A statement from Iraqi Kurdistan’s counter-terrorism service, which differs to the federal Iraqi service, said attacks by drones at the al-Harir airbase caused a fire at one of its fuel depots. It said the base had been evacuated of US-led forces on 20 October. US-led troops have been attacked at least 40 times in Iraq and Syria since early October over Israel’s devastating attack on Gaza in retaliation for Hamas militants’ 7 October attack on Israel. Forty-five US soldiers have been injured, US officials say. Washington blames the attacks on groups backed by Iran and says Tehran is ultimately responsible, a claim which Tehran denies, saying groups engaging in the attacks were doing so on their own accord. Iran-backed militias in Iraq have publicly stated that US assets will continue to be targeted as long as the US backs Israel in its war on Gaza. The latest attacks come after the White House said on Thursday the US military had struck targets in Syria to destroy weaponry and deter Iranian-backed separatist groups from targeting American personnel in the region. The US has occasionally carried out retaliatory strikes against Iranian-backed forces in the region after they attack American forces, including a strike on 26 October. The US defence secretary, Lloyd Austin, said in statement that Wednesday’s strikes were conducted by two F-15 fighters and were in response to the recent attacks against US forces. Austin said the attacks must stop. “If attacks by Iran’s proxies against US forces continue, we will not hesitate to take further necessary measures to protect our people,” he said. The Syrian Observatory for Human Rights said Wednesday’s strike killed nine people affiliated with Iran-backed groups in Syria, a toll that could not be independently confirmed. Reuters has reported that the US military was taking new measures to protect its Middle East forces during the increase in attacks by suspected Iran-backed groups, and was leaving open the possibility of evacuating military families if needed. The measures include increasing patrols, restricting access to base facilities and boosting intelligence collection, including through drone and other surveillance operations, officials said.