A powerful gas explosion caused multiple injuries on Saturday at a shopping mall in Florida, firefighters said.

Photos on US news outlets showed a large field of debris outside the shopping centre in the town of Plantation in south Florida.

The explosion occurred in a vacant pizza restaurant, according to police. The restaurant was destroyed, and nearby businesses were damaged.

The Plantation Fire Department said it was a gas explosion, and it reported "multiple patients."

At least 20 people were injured in the blast, two critically, according to officials.

The Plantation Fire Department said that the police force wished to alert locals of their activity in the area and requested that people avoid the area.

A major avenue running past the mall was shut down as police and firefighters investigated the explosion that occurred on Saturday morning in the town which is west of the popular beachside tourist spot of Fort Lauderdale.

The blast sent large pieces of concrete and steel debris about 100 metres across the street.

Video and photos posted on social media showed a part of the shopping complex with its roof reduced to rubble and reinforcings.

A police officer at the scene said there were no known fatalities.

This is a developing story, more to come.