Researches found debris from a medical transport plane that was carrying six people when it vanished over the Atlantic early on Saturday during a flight from Bermuda to Boston, the US Coast Guard said.

A statement from the Coast Guard issued on Saturday evening said crews searching off the coast of the Massachusetts island Nantucket “located a debris field confirmed to be from the aircraft”, described as an air ambulance.

Six passengers and crew on board were still unaccounted for at the time of the debris field’s discovery, a spokesperson for the Coast Guard said. Boats, planes and helicopters were launched after flight controllers lost contact with the air ambulance.

Air traffic controllers had difficulty communicating with the flight in its final moments.

“You’re coming in blind? Is that what you said?” a controller asked the pilot at about 12.46am. “Are you declaring an emergency, or no?”

According to a recording captured by LiveATC.net, the pilot’s response was not audible.

The air ambulance – a Gulfstream G100 – took off from Bermuda late on Saturday, carrying a patient, a family member and a four-person crew. The patient and family member were identified as citizens of Bermuda. The crew was identified as Canadian citizens, though the names of the people on board the flight were not immediately released.

As it neared Nantucket, the plane reported electrical failures, according to radio transmissions. Data from the website FlightAware shows the plane descended thousands of feet within three minutes and disappeared from radar shortly after at about 1am local time.

The Coast Guard said on Saturday evening that its William Sparling cutter boat would continue searching for those onboard the air ambulance through the night.

The agency reported that its crews searched roughtly 1,644 sq miles (4,258 sq km) for the aircraft in about 27 hours.

“Crews are continuing to search for the six people who were aboard the aircraft and the Coast Guard cutter William Sparling will continue search efforts throughout the night.”

Bermudian government officials said they had been in touch with the passengers’ families.

“My thoughts are with everyone on board and their families during this deeply worrying time,” Bermuda premier David Burt in a statement. “We are praying that all six people will be found safe, and we thank the search and rescue crews for their continuing efforts.”