The CEO of American Airlines expressed his 'deep sorrow' Wednesday night following the collision between an American Airlines passenger plane and a military helicopter. "First and most importantly, I'd like to express our deep sorrow about these events. This is a difficult day for all of us at American Airlines," Robert Isom said in a video message. "And our efforts now are focused entirely on the needs of our passengers, crew members, partners, first responders, along with their families and loved ones," he added. A jet carrying 60 passengers and four crew members collided Wednesday with an Army helicopter while landing at Ronald Reagan National Airport near Washington, prompting a large search-and-rescue operation in the nearby Potomac River. There were multiple fatalities, according to a person familiar with the matter, but the precise number of victims was unclear as rescue crews hunted for any survivors. Three soldiers were onboard the helicopter, an Army official said. There was no immediate word on the cause of the collision, but all takeoffs and landings from the airport were halted while helicopters from law enforcement agencies across the region flew over the scene. Inflatable rescue boats were launched into the Potomac River from a point along the George Washington Parkway, just north of the airport, and first responders set up light towers from the shore to illuminate the area near the collision site. At least a half-dozen boats are scanning the water using search lights.