Two brothers and the girlfriend of one of the men have been identified as the British victims of a helicopter crash in the Grand Canyon.
Becky Dobson, 27, Jason Hill, 32, and Stuart Hill, 30, died when the Papillon tour helicopter came down at about 5.20pm on Saturday, the Hualapai Nation Police Department said.
Three other Britons are in a critical condition after surviving the crash.
Brothers Stuart and Jason were on the trip with Stuart's girlfriend, Ms Dobson, to celebrate his 30th birthday.
Ms Dobson was a receptionist at a veterinary practice in Worthing, West Sussex and had previously been an au pair in Sydney, Australia.
On the surgery's website she described her favourite things to do as work with her horse Buddy, see her family and friends, and travel.
She added that her dream was to be a veterinary nurse.
Jason Hill was a corporate senior associate for law firm, Shoosmiths.
He was a graduate of the University of Southampton, and the college of law in Guildford, Surrey.
According to his LinkedIn profile, he was most recently based in the firm's Milton Keynes office, and helped advise companies on debt and equity investment, including via crowdfunding.
Stuart Hill worked for Mercedes, his father told the Evening Standard .
The Reverend Hill added: "The two brothers loved each other and were very close, and so our misfortune is their support - because they went together, and I will thank God every day for them."
He said they had saved for a year to go on the trip and were there as a group of six.
Three further Britons - named by police as Ellie Milward, 29, Jonathan Udall, 32, and Jennifer Barham, 39 - were airlifted to University Medical Centre in Las Vegas, Nevada, along with pilot Scott Booth, 42.
They are all said to be in critical condition, with high winds meaning the rescue chopper had to wait hours to leave the canyon.
"We are providing support to the families of six British visitors involved in a helicopter accident at the Grand Canyon on February 10, and we are in close contact with the US emergency services," a Foreign Office spokeswoman said.
The circumstances surrounding the crash - on the West Rim of the Canyon - are currently unknown.
Hualapai Police chief Francis Bradley said: "It's a very tragic incident.
"Yesterday, we were hampered by severe weather conditions, we had gusts up to 50mph. The terrain where the crash occurred... is extremely rugged."
Photos of the crash scene taken by eyewitness Teddy Fujimoto showed flames and dark smoke rising from the rocky terrain.
Mr Fujimoto, a Las Vegas photographer, was doing a wedding shoot at the time of the crash when he heard people shouting and saw them running towards the edge of a ravine. He followed them.
"There was a helicopter, flames, smoke," he said. "It was horrible... unimaginable."
He said he then heard two or three small explosions where the wreckage was, about 600ft (183m) below from where he was standing.
Windy conditions, darkness and the difficult terrain meant rescue crews had to be flown in to reach the helicopter's wreckage.
The survivors could not be airlifted out of the canyon until around 2am because of high winds, police said.
Federal Aviation Administration spokesman Allen Kenitzer said the Eurocopter EC130 aircraft sustained considerable damage.
The FAA and the National Transportation Safety Board will investigate the crash.
Papillon Airways says on its website that it is "the world's largest aerial sightseeing company" and that it provides "the only way to tour the Grand Canyon".
The company says it flies around 600,000 passengers a year over the Grand Canyon and on other tours.
In a statement, Papillon Group chief executive Brenda Halvorson said: "It is with extreme sadness we extend our heartfelt sympathy to the families involved in this accident.
"Our top priority is the care and needs of our passengers and our staff."
A Papillon helicopter was previously involved in a fatal Grand Canyon crash in 2001.
The pilot and five tourists from New York were killed, while one woman survived.