CAIRO, Egypt - A threatening radio message at the end of a video showing Iranian patrol boats swarming near U.S. warships in the Persian Gulf may have come from a prankster rather than from the Iranian vessels, the Navy Times newspaper has reported.

A video and audio of the Jan. 6 incident in the Strait of Hormuz featured a man in accented English saying "I am coming to you. ... You will explode after ... minutes."

Cmdr. Lydia Robertson, spokeswoman for the Fifth Fleet in Bahrain, said the Navy was still trying to determine the source of the transmission but believed it was related to the Iranian actions.

"The Iranian boats were coming close to the ships, making aggressive maneuvers and objects were being dropped into the water," she told The Associated Press.

However, the Navy Times, a weekly newspaper published by the Gannett company, quoted several veteran sailors as speculating the transmission could have come from a heckler widely known among sailors in the region by the ethnically insulting term "the Filipino Monkey."

The newspaper, which serves the Navy community, said U.S. sailors in the Persian Gulf have heard the prankster -- possibly more than one person -- transmitting "insults and jabbering vile epithets" on unencrypted frequencies.

"Navy women -- a helicopter pilot hailing a tanker, for example -- who are overheard on the radio are said to suffer particularly degrading treatment," the newspaper said Sunday. "Several Navy ship drivers interviewed by Navy Times are raising the possibility that the Monkey, or an imitator, was indeed featured in that video."

U.S. Navy officials at Fifth Fleet headquarters in Bahrain could not immediately be reached for comment. However, Navy officials have said they were unsure where the transmission came from.

The threat, however, ratcheted up tensions in the incident, which began when Iranian patrol boats swarmed around three U.S. Navy vessels near Iranian waters in the Strait of Hormuz.

Iran has denied that its boats threatened the U.S. vessels and accused Washington of fabricating video and audio it released. Iran's government has released its own video, which appeared to be shot from a small boat bobbing at least yards from the American warships.

The Navy Times quoted Rick Hoffman, a retired captain, as saying a renegade talker repeatedly harassed ships in the Gulf in the late 1980s.

"For 25 years there's been this mythical guy out there who, hour after hour, shouts obscenities and threats," he said. "He could be tied up pierside somewhere or he could be on the bridge of a merchant ship," Hoffman said.