Armed robbers some wearing pig masks have stormed a Rolex store at the iconic Bellagio hotel in Las Vegas.
Guests tweeting from the building reported chaotic scenes at around 1AM local time (8AM GMT).
There are not thought to be any casualties but a stampede was reported as people fled for cover.
The number of gunmen is unclear.
Police are at the scene but the perpetrators are still at large.
More to follow...