A senior U.S. official has confirmed to Fox News that the U.S. service members who lost their lives and were injured in a Saturday ambush in Syria were part of the Iowa National Guard.

The attack, carried out by an ISIS gunman wielding an automatic weapon, occurred in the central Syrian town of Palmyra. Tragically, the assault resulted in the deaths of two Iowa National Guard soldiers and an American civilian translator, according to the official.

Additionally, three U.S. soldiers sustained injuries during the incident.

U.S. forces are seen on patrol in the northeastern Syrian city of Qamishli within the Hasakeh province as of January 9. (Delil Souleiman/AFP via Getty Images)

Initial reports indicate that the attacker had previous ties with the Syrian government forces as a low-ranking member of the Syrian Security Forces, before subsequently aligning with ISIS, the official revealed.

“He was not a part of the official delegation that was being escorted by the US and Syrian troops,” the official said. “… This would not be considered a ‘green on blue’ incident because the Syrian gunman was not part of the US/Syrian partnered delegation.”

President Donald Trump attends the 126th Army-Navy Game between the Army Black Knights and the Navy Midshipmen, Saturday, in Baltimore, Md.  (Tasos Katopodis/Getty Images)

Earlier Saturday, U.S. Central Command confirmed the deaths and injuries were a “result of an ambush by a lone ISIS gunman in Syria.”

President Donald Trump warned that there will be “very serious retaliation” following the ambush.

“We mourn the loss of three Great American Patriots in Syria, two soldiers, and one Civilian Interpreter. Likewise, we pray for the three injured soldiers who, it has just been confirmed, are doing well,” Trump wrote on Truth Social. 

U.S. Army soldiers in northeastern Syria.  (John Moore/Getty Images)

Trump added, “This was an ISIS attack against the U.S. and Syria, in a very dangerous part of Syria, that is not fully controlled by them.”

Last month, two West Virginia National Guard members were ambushed and shot near the White House in Washington, D.C., in a targeted attack that left one soldier dead.