Washington, D.C., Mayor Muriel Bowser is holding a press conference updating the public on rescue efforts after a military helicopter collided with a civilian airliner above the Potomac River. “Tonight,

Rescuers are searching for survivors as the water in the Potomac River is thought to be around 35 degrees. NBC News' Peter Alexander describes the scene near the site where an American Airlines regional jet collided with a helicopters.

An extensive search and rescue operation is currently under way after an American Airlines flight collided in mid-air with a helicopter in Washington DC, with both crashing into the Potomac River. Emergency services chief John Donnelly has said conditions are "extremely rough" in the dark and with icy temperatures.