A Spanish tech boss and his family were killed when their helicopter crashed into a river in New York.

Agustin Escobar, an executive for Germany-based tech company Siemens, and his family were flying over the Hudson River when the aircraft plunged from the sky on April 10 afternoon.

Shocked onlookers watched as the helicopter smashed upside-down into the water, sending debris flying.

Footage shows documents and a part of a helicopter door floating in the water near a bridge.

Emergency responders arrived at the scene after receiving numerous 911 calls at around 3:17 pm local time. Four people were declared dead, while two children were taken to the Jersey City Medical Center, where they were pronounced dead.

New York Police Commissioner Jessica Tisch said the aircraft was a Bell 206 chopper operated by New York Helicopter Tours.

Governor Kathy Hochul added: 'Six innocent souls have lost their lives, and we pray for them and their families.'

Authorities were collecting the wreckage of the aircraft from the river.