At least four people have died after a train collided with a bus in Mississippi, police have confirmed.

The tour bus was dragged 91m (300ft) along the track following the crash in Biloxi.

According to the Sun Herald newspaper, a total of 42 people were on the bus at the time, and 35 were injured.

It is understood the bus had been stuck on the railroad for about five or 10 minutes when the train hit - and although officials are unsure why the bus had stopped, engine failure is a possibility.

Craig Robinson, who witnessed the crash, told the Sun Herald: "My first instinct was to get down there and tell people to get off the bus, but by the time I got there the train had already hit it."

Rescuers have been removing trapped passengers through emergency windows, and at least one person has been taken to hospital by air ambulance.

The tour bus had been travelling from Austin in Texas when it crashed shortly after 2.00pm (8.00pm Irish time), and it is thought those on board may have been heading to one of Biloxi's eight casinos.

Biloxi's police chief, John Miller, said: "It's a terrible tragedy and I know there's a lot of families that are going to be impacted."

Mayor Andrew Gilich added that it was "a tragic day for the city".

CSX Transportation, which was operating the freight train, said it was travelling from New Orleans to Alabama at the time of the crash - and its train crew was not injured.

A spokesman said the train had three locomotives, and 27 of the 52 cars were loaded.

The National Transportation Safety Board (NTSB) said it was aware of the crash and monitoring.

NTSB is gathering information about today’s accident involving a freight train and a bus in Biloxi, MS.

— NTSB_Newsroom (@NTSB_Newsroom) March 7, 2017