Fox News national security correspondent Jennifer Griffin reported that a senior foreign diplomat had told the network that the deadly suicide attack on U.S. troops in Syria was a "direct result of the announcement made by President Trump that U.S. forces are pulling out."

"U.S. allies remain up in arms about the U.S. announcing it is pulling out of Syria," Griffin reported on Fox News chief anchor Shepard Smith's newscast on Wednesday afternoon.

"A senior foreign diplomat tells Fox News, 'This attack today is a direct result of the announcement made by President Trump that U.S. forces are pulling out. These troops had a bulls-eye on them when the president telegraphed that he was ordering a pullout'," she added.

Griffin did not name the diplomat.

The White House did not immediately reply to a request for comment from The Hill.

The Islamic State in Iraq and Syria (ISIS) has claimed responsibility for an explosion that killed four Americans, including two troops, during what the U.S. military called "a routine patrol."

The White House condemned what it called a "terrorist attack."

"President Trump and I condemn the terrorist attack in Syria that claimed American lives and our hearts are with the loved ones of the fallen," Vice President Pence said in a statement. "We honor their memory and we will never forget their service and sacrifice."

The causalities included two U.S. service members, a defense contractor and a Defense Department civilian.

In a surprise move, President Trump tweeted on Dec. 19 that the U.S. would pull the approximately 2,000 troops stationed in Syria, saying ISIS had been defeated.

The action helped spur the resignation of Defense Secretary James Mattis.

However, the U.S. has since gone slow with the pullout, with national security adviser John Bolton saying last week that there is no concrete timetable for withdrawal.

"There are objectives that we want to accomplish that condition the withdrawal," Bolton told reporters during a trip to Jerusalem. "The timetable flows from the policy decisions that we need to implement."