WASHINGTON, Dec. 30-- U.S. federal and local security officials are tightening security in high-profile locations tied to New Year's celebrations, considering possible security threats on the New Year holiday, local media reported on Wednesday.

According to the U.S. TV network CNN, U.S. President Barack Obama at a briefing was told of possible security threats over the year-end holidays before his departure for Hawaii vacation.

Among the threats was one originating overseas warning of possible attacks in three major U.S. cities, New York, Los Angeles and Washington, between the Christmas and New Year holidays, the report quoted unnamed senior officials as saying. The threat was uncorroborated and was based on a single source, it added.

According to the report, U.S. security officials are tightening security in high-profile locations on New Year's celebrations, including New York's Times Square and the Rose Bowl festivities near Los Angeles.

New York says more than 6,000 police officers, canine units, air and water patrols and rooftop snipers will be deployed around Times Square, the biggest such deployment ever, to ensure the safety of expected 1 million visitors for the New Year's Eve ball drops.

New York Mayor Bill de Blasio said Tuesday the security measure that will be in place at the Big Apple landmark are "extraordinary."