A search and rescue effort continues after a bridge collapse in Baltimore.  

A fully laden container ship rammed into one of the supports and the bridge crumpled into the water below. 

Those on board the ship had time to raise the alarm and the bridge was closed. 

At least six people remain unaccounted for. 

Those missing are believed to be construction workers who were working on potholes on the bridge at the time. 

US correspondent Mitch McCann told Mike Hosking that it could have a huge economic impact on the state. 

He says it's one of the biggest ports in the US, specialising in shipping motor vehicles and farming equipment and bringing in over US $1 billion last year. 

US President Joe Biden says around 850,000 ships go through the port a year and 15,000 jobs depend on it. 

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