The Pentagon says U.S. troops in Syria came under artillery fire from the Turks on Friday, in an area where Turkey knows Americans are present.
Navy Capt. Brook DeWalt, a Pentagon spokesman, says the artillery explosion came within a few hundred meters of the area where U.S. troops were.
He says no troops were injured and U.S. forces have not withdrawn from Kobani.
Turkey says the U.S. was not the target.
DeWalt warns that Turkey must avoid actions that could result in immediate defensive action by the U.S.
This is the first time a coalition base has been in the line of fire since Turkey's offensive into Syria began Wednesday.