The U.S. Coast Guard on Sunday suspended the search for six people in a medical jet that went missing near Nantucket, Massachusetts, a day after debris from the plane was found.

Search and rescue crews operated for approximately 66 hours to locate four Canadians and two Bermudian nationals on the plane that was traveling to Boston from Bermuda early Saturday morning, according to the U.S. Coast Guard.

The Canadian-registered air ambulance jet had four crew members and two passengers aboard. Their next of kin have been notified, the Coast Guard said.

Earlier, the Coast Guard confirmed that a debris field belonging to the missing Gulfstream G-100 was found Saturday night. The search for the missing passengers continued overnight off the coast of Nantucket, according to the Coast Guard’s Northeast District, and spanned 4,445 miles before it was suspended.

The Coast Guard outlined the extensive assets involved in the search, including an HC-144 Ocean Sentry airplane, an HC-130 Hercules airplane, an MH-60 Jayhawk helicopter, a 47-foot Motor Lifeboat and the FRC William Sparling, a Sentinel-class fast response cutter.

“Suspending a search is not an easy decision,” Rear Adm. Matthew Lake, Commander of the Northeast District, said in a statement. “We express our deepest condolences to the families and loved ones affected by the tragedy and our gratitude for our partner agencies who helped support search efforts.”

The plane took off from Bermuda’s L.F. Wade International Airport at about 11:40 p.m. ET on Friday, according to data from FlightAware. It went missing after about 1 hour and 45 minutes in the air. FlightAware data show it quickly dropped from about 24,000 feet to 11,000 feet before losing contact. It had been set to land at Boston’s Logan International Airport at about 1:30 a.m. local time.

The Federal Aviation Administration confirmed it had lost contact with the plane around 1 a.m. local time Saturday and issued a Search and Rescue Alert Notice for the Gulfstream.

Canada’s foreign policy department said it was “deeply concerned by the disappearance” of the plane in a statement Sunday.

“Our thoughts are with everyone on board and their loved ones,” the statement said. “We thank the U.S. Coast Guard and all those involved in the search for their tireless efforts.”

Officials haven’t been able to identify the aircraft components found among the debris, said Kastriot Kastrati, coordinator of the Coast Guard’s search and rescue mission, at a briefing Sunday.

“It’s very difficult at this point to identify exactly what those components are,” he said. “The debris that we have recovered, we’ve safeguarded and kept for future investigative efforts.”

The National Transportation Safety Board told CBS News on Sunday that it is monitoring the situation.

“My thoughts are with everyone on board, as well as their families, loved ones and colleagues during this incredibly difficult time,” Steve MacKinnon, Canada’s minister of transport, said in a statement.