The China-based travel agency that organised a trip to North Korea for an American college student who died after being released in a coma from detention said it would no longer take US citizens to the country.
Young Pioneer Tours said on its Facebook page that the death of 22-year-old Otto Warmbier shows the risk facing American tourists in North Korea "has become too high".
Mr Warmbier died in Ohio yesterday, days after being released by North Korea.
The tour operator said it was denied any opportunity to meet him after his detention, and that the way it was handled was "appalling".
Otto Warmbier's family says the 22-year-old "has completed his journey home". They did not cite a cause of death.
"Unfortunately, the awful, torturous mistreatment our son received at the hands of the North Koreans ensured that no other outcome was possible beyond the sad one we experienced today," his parents said.
Doctors had described Mr Warmbier's condition as a state of "unresponsive wakefulness" and said he suffered a "severe neurological injury" of unknown cause.
He arrived in Ohio on June 13 after being held for more than 17 months.
The University of Virginia student was accused of trying to steal a propaganda banner while visiting with a tour group and was convicted of subversion. He was put before North Korean officials and journalists for a televised "confession".
"I have made the worst mistake of my life," he said, choking up as he begged to be allowed to reunite with his parents and two younger siblings.
He was sentenced in March last year to 15 years in prison with hard labour. His relatives said they were told he had been in a coma since soon after his sentencing.
Doctors said he suffered extensive loss of brain tissue and "profound weakness and contraction" of his muscles, arms and legs. His eyes opened and blinked but without any sign that he understood verbal commands or his surroundings.
Unresponsive wakefulness is a new medical term for persistent vegetative state.
Patients in this condition who have survived a coma can open their eyes, but they do not respond to commands.
People can live in a state of unresponsive wakefulness for many years with the chances of recovery depending on the extent of the brain injury.
North Korea said Mr Warmbier went into a coma after contracting botulism and taking a sleeping pill. Doctors in Cincinnati said they found no active sign of botulism or evidence of beatings.
President Donald Trump said: "A lot of bad things happened, but at least we got him home to be with his parents." He called North Korea a "brutal regime".
Mr Warmbier grew up in the Cincinnati suburb of Wyoming. Wyoming City Schools released a statement saying the organisation was "deeply saddened" by his death.
"The countless contributions he made to his school and community through his leadership, actions and limitless enthusiasm will be felt far into the future," the school district said.
He had planned to study in China in his third year of college and heard about Chinese travel companies offering trips to North Korea. He was leaving the country on January 2 last year when he was detained at the airport.
Three Americans remain held in North Korea. The US government accuses Pyongyang of using such detainees as political pawns. North Korea accuses Washington and South Korea of sending spies to overthrow its government.