U.S. forces were targeted in four attacks in Iraq and Syria on Thursday but suffered no casualties, the Pentagon said, in the most geographically widespread series of strikes on U.S. assets in a single day since the Israel-Hamas conflict started.

Pentagon deputy press secretary Sabrina Singh said the U.S. has now been attacked 46 times since Oct. 17.

“If these attacks continue against our personnel, we won’t hesitate at a time and place of our choosing to respond again,” Singh told reporters at a briefing. 

A joint patrol of U.S. forces and the Iraqi counter-terrorism service was targeted by an explosive device near the northern city of Mosul on Thursday, causing damage to a vehicle but no casualties, two security sources said.

A U.S. military official confirmed a U.S.-led coalition convoy encountered an improvised explosive device (IED) blast in the vicinity of Mosul Dam and said no casualties were reported.

A separate U.S. official, speaking on the condition of anonymity, said that the four attacks in the past 24 hours resulted in three U.S. troops sustaining minor injuries and they had returned to duty, the official added.

Armed drones targeted the al-Harir air base in Erbil and the Ain al-Asad air base west of Baghdad, both of which house U.S. and international forces. The drones were downed by air defenses 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 added that the base had been evacuated of U.S.-led coalition forces on Oct. 20.

U.S. and coalition troops have been attacked at least 40 times in Iraq and Syria since early October over Israel's devastating siege of Gaza in retaliation for Hamas militants' Oct. 7 cross-border attack.

Forty-five U.S. soldiers have suffered traumatic brain injuries or minor wounds prior to Wednesday, U.S. officials say.

The U.S. 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 U.S. assets will continue to be targeted as long as the U.S. backs Israel in its war on Gaza.

The latest attacks come after the White House said on Thursday the U.S. military had struck targets in Syria to destroy weaponry and deter Iranian-backed separatist groups from targeting American personnel in the region.

The United States has occasionally carried out retaliatory strikes against Iranian-backed forces in the region after they attack American forces, including a strike on Oct. 26.