ROME (AP) _ The U.S. military today denied a report that an American base in Italy had been placed on alert to receive F-16 fighter jets for a NATO operation to clamp down on rebel Serbs in Bosnia.

The report by the Italian news agency ANSA also said that up to 3,000 American soldiers were expected to arrive soon.

''We are not on alert and are not moving troops or F-16s to northern Italy,'' Navy Cmdr. Ron Morris, a spokesman for the U.S. European Command headquarters in Stuttgart, Germany, told The Associated Press.

Earlier, the spokesman at the base at Aviano, near Udine in northeastern Italy, would not comment.

Reports from NATO headquarters in Brussels have said the United States and its allies are considering various military options to enforce a flight ban over Bosnia, including damaging airfields and shooting down Serb aircraft.

The actions would be aimed at halting the bloodshed in Bosnia. Serbia has been blamed for instigating the violence, which has left at least 17,000 dead since Bosnia seceded from Serb-dominated Yugoslavia in February.

The base spokesman, Paolo Parchi, said NATO surveillance planes are making daily flights from Aviano, monitoring Bosnia from over Hungary.