WASHINGTON - Authorities in the US city of Philadelphia cleared a US Airways flight of hazardous material Wednesday, after it made an emergency landing over an alleged bomb threat, local media said.

A phone call claiming there was a suspicious device on Flight 777 from Shannon, Ireland, came in to the authorities at around 1: 30 pm (1730 GMT), and the Philadelphia-bound jet landed about 25 minutes later at Philadelphia International Airport and was taken to a secure area for a search, according to WPVI-TV of Philadelphia.

However, the FBI, the Transportation Security Administration and Philadelphia police found nothing suspicious and eventually cleared the plane at around 3:00 pm (1900 GMT).

US Airways said there were 171 passengers and eight crew members onboard the plane, a Boeing 757.

After the all-clear was given, the plane was brought back to the airport area, as well as the passengers' luggage. There were no reports of any injuries.

TV reports showed people coming down a walkway from the plane, which had a number of police vehicles nearby with lights flashing. At least three airport buses have also been brought next to the plane.

The phone call that triggered the alarm in the emergency landing was now being investigated. It was unclear who made the call at the moment.

US authorities have been in heightened state of security, after chatters of possible terrorist attacks against US interests were uncovered between high-level al-Qaida leaders.