Key Bridge collapse mapped: Where is the Baltimore bridge in the US and where did incident take place?

A “mass casualty incident” has been declared after a bridge in Baltimore collapsed, leaving authorities searching for seven people who have fallen in the river.

A part of the Francis Scott Key Bridge, in Maryland, came down after a container ship hit it early on Tuesday morning.

The 1.6 mile-long bridge carries Route 695 and is the third longest length of unsupported roadway in the world. It crosses the Patapsco River in the southeastern corner of Baltimore City, which is a major sea port on the Atlantic Ocean coastline.

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The bridge was struck by a large vessel at around 1.30am local time, with multiple vehicles falling into the water below. The boat also caught on fire and sank.

Kevin Cartwright, director of communications for the Baltimore Fire Department, told news agency AP that 911 calls reported a vessel travelling outbound from Baltimore had struck a column on the bridge, causing it to collapse.

Multiple vehicles were on the bridge at the time, including one the size of a tractor-trailer.

Mr Cartwright said: “This is currently a mass casualty incident and we are searching for seven people who are in the river.”

He said it’s too early to know how many people were affected, but called the collapse a “developing mass casualty event”.