The mayor of Los Angeles, Antonio Villaraigosa, says authorities know of no credible threats to the western U.S. city, following a warning from a suspected al-Qaida member.
The warning came in a videotaped statement aired by the U.S. television network ABC on Sunday. A masked man on the tape says "Allah willing," Los Angeles and the Australian city of Melbourne will be attacked.
ABC says the tape was delivered to its office in Pakistan on Saturday. It says the speaker is probably Adam Gadahn, a U.S. citizen wanted for questioning by the FBI for possible terrorist activity.
Officials in both Los Angeles and Melbourne say the tape was meant to instill fear, and have advised residents to go about their normal lives.
U.S. intelligence officials have refused to comment on whether the taped warning is authentic.