A fire that damaged construction equipment at the site of a Tennessee Islamic centre has been ruled arson.

Officials in Murfreesboro have offered a $20,000 (£13,000) reward for help finding the person they say doused a lorry in diesel and then ignited it.

The FBI said it had yet to determine whether the fire was a hate crime and would not say if it has any suspects.

Saturday's incident came amid growing anti-Muslim animosity and opposition to new mosque building across the US.

The Islamic Center of Murfreesboro has outgrown its current space and is constructing a new campus.

Mosque leaders note Muslims have lived and worshipped in Murfreesboro without any problems.

But anti-Muslim protests have risen in recent months, provoked in part by opposition to a developer's plans to build an Islamic community centre near the site of the World Trade Center in New York City.