Geography student Jonathan Dorey, from Guernsey, was last seen on the Virginia Commonwealth University campus in Richmond, Virginia, on March 2.

Mr Dorey, known as Jonny, is a University of the West of England student on an exchange visit.

He disappeared after attending a morning lecture.

His mobile phone was turned off and his bicycle vanished, according to reports.

The university is offering a $5,000 (£3,300) reward for information which helps locate the missing student.

There is also a campaign on networking site Twitter - search @findJonnyDorey - to locate him.

John Bennett, VCU senior vice-president, said: "As we continue the search for Jonathan, our thoughts are with his family and friends."

Police say there is no sign of foul play and his parents have travelled to the US to aid the search.

Mr Dorey is described as around 6ft tall, with brown hair and was last seen wearing a white and blue plaid jacket, navy blue backpack, dark jeans and black trainers.