The Francis Scott Key Bridge along I-695 in Maryland collapsed into the Baltimore harbor early Tuesday morning following a "ship strike," Maryland transportation officials said.

A livestream of the bridge appeared to show a cargo ship colliding with a support beam, causing the bridge to break and fall into the Patapsco River. 

Emergency crews are on-site attempting to save at least 7 people in the water in what officials have called a mass casualty event. There were no specific number of deceased. 

It is believed that a Singapore-flagged cargo ship struck the heavily-traveled bridge. The large vessel then caught fire before it sank.

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The Maryland Transportation Authority said on social media that all lanes are closed in both directions and that traffic is being detoured. Later, it urged drivers to avoid the I-695 southeast corridor and to instead use I-95 or I-895.

"[At] 1:35 a.m., Baltimore City police were notified of a partial bridge collapse, with workers possibly in the water, at the Francis Scott Key Bridge," a spokesperson for Baltimore Police said in a statement to Fox News.

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Multiple emergency crews are on the scene assessing the damage and investigating the cause, Fox Baltimore reported.

As of 2:45 a.m., all live camera feeds for the bridge, along I-695, on the Maryland Transportation Authority website are offline.

The iconic bridge is named after Francis Scott Key, who authored the American National Anthem, "The Star-Spangled Banner." 

This report is developing and will be updated.

Fox News' Melissa Summers contributed to this report.