Hundreds of people ran for their lives as a truck rammed into a mall in central Stockholm on Friday (April 7) afternoon, a witness said.

"I saw hundreds of people ran, they ran for their lives," a woman, identified only as Anna, told Swedish media Aftonbladet. "I turned and ran as well."

Many were injured when the truck drove into a crowd in shopping district of Drottninggata in Sweden's capital, Swedish security police said.

Reports put the number of dead at between two and five.

The smoking truck was seen jutting out of the Ahlens department store.

Mr Jan Granroth was in a shoe store nearby when he heard screams.

"We stood inside a shoe store... and people start screaming. So I look out at the store, so I see a huge truck slams into the wall opposite," Aftonbladet quoted him as saying.

Mr Christoffer Ung was shopping at Ahlens when the truck struck the building. The falling wall came towards him like an "avalanche", he told Svenska Dagbladet, another Swedish news site.

"People turned in panic and ran for the exits," he said. "When I came out of the building, I saw flames coming out of the building."

Another witness said he saw at least two people being run over.

"I ran as fast as I could from there," said another man, identified only as Mr Dimitris.

The injured lay on the streets as emergency responders and doctors went to them.

Body-like forms covered by orange blankets were seen on the street.

The truck is understood to have been stolen or hijacked from a brewery, the Daily Mail reported.

There were also reports of shots at a second incident.