SYRIA — (AP) U.S. officials say an American airstrike has hit pro-Syrian government forces in southern Syria as they were setting up fighting positions in a protected area.

The officials say the strike near Tanf hit a tank and a bulldozer and forces there, but it was not clear if they were Syrian army troops or other pro-government allies.

One official says the pro-regime forces had entered a so-called “de-confliction” zone without authorization and were perceived as a threat to U.S.-allied troops there. The officials say the strike was a defensive move to protect the U.S. allies. It wasn’t clear if U.S. forces were there.

The officials weren’t authorized to speak publicly on the matter and demanded anonymity.

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