U.S. naval forces were dispatched toward the waters off Yemen's coast Sunday after an appeal from a crew aboard a sailboat who feared they were about to be attacked by pirates, but a Navy official said it was "a false alarm."

Earlier, Italian port authorities in Rome said a Dutch and two U.S. warships in the area were dispatched to aid a U.S.-flagged sailboat under attack by pirates, after an Italian ship in the area picked up a distress call.

Lt. Cmdr. Charlie Brown of the U.S. 5th Fleet in Bahrain said it turned out to be "a false alarm."

"There were some folks who were sailing, and they got nervous when they saw some small boats in area where there have been attacks in past. We sent forces to take a look at situation and they were able to determine there was no attack," Brown said.

Brown did not give details.

Piracy has risen sharply in the region, with several pirate groups operating along Somalia's lawless coastline, which is across the Gulf of Aden to the south of Yemen.

On March 18, two U.S. Navy ships exchanged gunfire with suspected pirates, killing one and wounding five. No U.S. sailors were injured. Somalis involved in that incident also claimed they were patrolling Somali waters to stop illegal fishing when the U.S. ships fired on them.

Two boats of pirates also attacked a luxury cruise liner carrying mostly American as well as Australian and European passengers in November, but the ship outran them by changing course and heading out to sea.