The plane was met by police and FBI agents

A US Airways flight was diverted to Philadelphia after a young Jewish man's prayer items triggered a bomb scare, Philadelphia police said.

The incident arose when the man used a phylactery, a small black box Orthodox Jews strap to their head as part of their prayer rituals, police said.

The man was not arrested and the plane landed without incident.

US airports are on high alert after a Nigerian man was held over an alleged bomb plot on a plane last month.

His device allegedly malfunctioned and he was quickly overpowered by passengers and crew on the flight from Amsterdam to Detroit.

The latest incident took place on a 50-seat regional jet originally bound for Louisville, Kentucky from New York's LaGuardia airport. It landed in Philadelphia at about 0900 local time (1400 GMT).

Phylacteries - called tefillin in Hebrew - are two small boxes of black leather, with straps attached to them.

Observant Jewish men are required to place one box on their head and tie the other one on their arm as part of their morning prayers.