Donald Trump supporters were hospitalised after hundreds were left stranded in the freezing cold after a rally.

The President's rally in Omaha, Nebraska last night ended in chaos after traffic jams prevented buses reaching attendees.

Trump flew off on Air Force One immediately after speaking at the rally.

But supporters of the President, including many elderly attendees, were left exposed to the elements for several hours.

At least seven people were taken to hospital, according to local sources.

Election frontrunner Joe Biden slammed Trump over the fiasco.

"Just look what happened last night in Omaha, after the Trump rally ended, hundreds of people, including older Americans and children, were stranded in subzero freezing temperatures for hours," he told reporters.

"Several folks ended up in the hospital. It's an image that captured President Trump's whole approach to this crisis ... He gets his photo-op and then he gets out."

He added: "He makes a lot of big pronouncements, but they don't hold up."

The Trump campaign said the problems were due to the unexpectedly large crowds.

Air Force One departed the rally at Eppley Airfield around 9pm last night.

Around 25,000 people were taken to the rally by 40 buses, which ran from 10am until 8am.

It's understood at least 30 people, including a wheelchair user and a family with small children, were among those who required medical attention.

The Trump campaign said: "President Trump loves his supporters and was thrilled to visit Omaha last night.

"Despite the cold, tens of thousands of people showed up for his rally. Because of the sheer size of the crowd, we deployed 40 shuttle buses — double the normal allotment — but local road closures and resulting congestion caused delays.

"At the guest departure location, we had tents, heaters, generators, hot cocoa, and handwarmers available for guests.

"We always strive to provide the best guest experience at our events and we care about their safety."