An airstrike on a weapons warehouse, center, in eastern Syria on November 8, 2023. The strike targeted a facility linked to Iranian-backed militias. [AP Photo]

Iranian-backed militias do not appear to be backing down despite a U.S. airstrike thought to have largely destroyed a key weapons storage facility in eastern Syria.

The Pentagon on Thursday hailed the strike, carried out by two U.S. F-15 fighter jets late Wednesday, as a success, citing a series of secondary explosions that left the building "non-usable." But U.S. officials also admitted that, at least for now, it failed to slow the pace of attacks by Iranian-backed militias on U.S. forces in the region.

A U.S. official told VOA on Thursday that following the U.S. airstrike, Iranian-backed militias launched four drone and rocket attacks against U.S. troops and bases - three in Syria and one in Iraq.

One of the attacks, late Wednesday targeting the U.S. facility in the Green Village in Syria, injured three troops.

Officials said two of the troops were diagnosed with traumatic brain injuries, or TBI, but that none of the injuries was serious and that all three returned to duty.

The officials also said that none of the drone and rocket attacks damaged any U.S. infrastructure.

"These attacks have been, for the majority, unsuccessful," Pentagon deputy press secretary Sabrina Singh told reporters Thursday.

"Thankfully, none of our troops have been injured seriously and our infrastructure at the bases that have been targeted, we have not experienced significant damage," she added.

U.S. bases and facilities have come under attack at least 46 times since Iranian-backed militias began targeting U.S. forces in Iraq and Syria last month in a show of support for Hamas in its fight against Israel.

Since October 17, 56 U.S. troops have been injured, with 25 diagnosed with TBI as a result of the blasts from exploding rockets or drones. Still, the Pentagon said all of the injuries were minor, and that all injured forces have returned to duty.

Pentagon officials also note that most of the injuries were incurred before the U.S. launched a first set of self-defense strikes, targeting two weapons and storage facilities used by Iranian proxies in Syria on October 26.

Wednesday's strike targeted a larger weapons storage facility in Syria's Deir el-Zour province that belonged to Iran's Islamic Revolutionary Guard Corps. U.S. officials said the facility had been providing many of the Iranian-linked groups with rockets and other materials used to launch attacks on U.S. forces.

Pentagon officials on Thursday voiced optimism that the operation would have the intended effect.

"We know that there were secondary explosions. We know that the facility was significantly damaged," Singh said. "We feel confident we were able to degrade their capabilities."

"We won't hesitate to take further necessary measures to protect our people and to do so at a time and place of our choosing," she added.

Houthis

The Pentagon on Thursday also officially confirmed that Iranian-backed Houthi rebels in Yemen had successfully shot down a U.S. drone flying over the Red Sea.

Singh told reporters there were indications that the U.S. MQ-9 drone landed in the water and that the Houthis tried to recover it before it sank.

"We know that there was an attempt by Houthis to try and recover the MQ-9 but it is unlikely that they will be able to retrieve anything of significance," she said. "We [the U.S.] are not right now looking to recover anything either."

In recent weeks, the United States has bolstered its force presence in the Middle East, sending two aircraft carrier strike groups, dozens of fighter jets and a ballistic missile submarine to the region to deter Iran and its proxies from expanding the conflict between Israel and Hamas.