Iran released video footage showing a drone shadowing U.S. military forces operating in Syria just a day before an unmanned aerial vehicle launched a strike on American forces in the war-torn country, a move that has raised concerns among U.S. officials about the Islamic Republic's increasing willingness to use military force in the region.

Iran's release of the video—which shows it using a drone to monitor U.S. operations as a Farsi-language narrator threatens to strike American forces—comes as the American military on Thursday was forced to shoot down a drone in Syria that was firing on coalition forces.

The Thursday attack, which U.S. military officials say was sponsored by Syrian-regime allies—which include Iran—highlights the increased threat posed by the Islamic Republic to U.S. forces operating in Syria.

While U.S. military officials would not initially confirm the drone was Iranian in origin, the timing of the attack and release of video footage by Iran has fueled speculation among national security insiders that Iran is stepping up its operations to counter U.S. military forces in Syria. U.S. officials later said the drone was likely connected to Iran and Hezbollah.

Iran has served as the chief defender of Syrian President Bashar al-Assad. The Islamic Republic has sent scores of fighters into the country, including specialized Revolutionary Guards Corps (IRGC) militants, and has mobilized its terror proxy Hezbollah to take up arms there as well.

The latest drone strike on U.S. forces in Syria has only heightened concerns among American officials that Iran has pivoted to attacking U.S. coalition forces in the country, a move that is likely to escalate tensions between Tehran and the Trump administration.

One State Department official, speaking on background, told the Washington Free Beacon the Trump administration has deep and ongoing concerns about Iran's "destabilizing activities" in Syria and the Middle East.

"We are deeply concerned by Iran's destabilizing activities in the region whether they are supporting the Assad regime, backing terrorist organizations like Hezbollah, or supporting violent militias that undermine governments in Iraq and Yemen," the official said. "Iran remains designated as a State Sponsor of Terrorism and we will continue to hold the Iranian government accountable for its actions."

U.S. military forces announced Thursday afternoon that they had shot down a "pro-Syrian regime" drone that fired on American-backed forces. While officials did not name Iran as the culprit, the timing of the strike and technology involved points to Tehran's involvement.

"The pro-regime UAV, similar in size to a U.S. MQ-1 Predator, was shot down by a U.S. aircraft after it dropped one of several weapons it was carrying near a position occupied by Coalition personnel who are training and advising partner ground forces in the fight against ISIS," U.S. military officials with Central Command, or CENTCOM, said in a situation report.

"The shoot down follows an earlier engagement in the day in which Coalition forces destroyed two pro-regime armed technical vehicles that advanced toward Coalition forces at At Tanf inside the established de-confliction zone threatening Coalition and partner forces," according to U.S. military officials.

The United States will continue to take forceful action to protect its assets in Syria, according to CENCTOM.

"The demonstrated hostile intent and actions of pro-regime forces near Coalition and partner forces in southern Syria, however, continue to concern us and the Coalition will take appropriate measures to protect our forces," CENTCOM said.

The footage of Iran using a drone to track U.S. military assets was released on Wednesday, just a day before the strike on American-backed forces.

The video, which was initially published on a Hezbollah-run television station, includes Farsi language narration stating, "This is an American drone. […] We could shoot you down anytime, but we take pity on you."

The narrator identifies an American drone in the footage as being tracked by "Iran's drones."

Tony Badran, a Syria expert at the Foundation for Defense of Democracies, told the Free Beacon that Iranian-backed forces have been intent on expanding their presence in Syria for some time.

"Before the U.S. struck them the first time, Hezbollah's war media published drone footage of what it claimed were U.S. and allied forces in Jordan, along with declarations of intent to move into that area. Following the second U.S. strike on them a couple of days ago, Hezbollah's war media has made direct threats to target U.S. and U.S.-backed forces in Syria and ‘its neighborhood,'" Badran said. "Iranian forces made similar threats, and posted the video of an Iranian drone shadowing an alleged U.S. drone, threatening that they could target the drone at will."