text: The service was held at the 22-year-old's school in Ohio, before his burial at a nearby cemetery.
  His death has heightened tensions between the US and North Korea.
  Pyongyang has called President Donald Trump a "psychopath", while he describes N Korea as a brutal regime.
  Pyongyang's official Rodong Sinmun newspaper claimed Mr Trump might launch a pre-emptive strike on North Korea to divert attention from his domestic difficulties, and warned South Korea "that following psychopath Trump... will only lead to disaster".
  Earlier in the week, after announcing Mr Warmbier's death, President Trump said he was determined to "prevent such tragedies from befalling innocent people at the hands of regimes that do not respect the rule of law or basic human decency".
  The thousands of funeral goers formed two lines as Mr Warmbier's coffin was carried into Wyoming High School for the 45-minute service, and then along the three-mile route to the cemetery.
  There was only space for 800 people inside the school's auditorium so most attendees watched the service on monitors in overflow rooms, CNN reports.
  Mr Warmbier's brother and sister, along with some friends, spoke during the service. Bagpipes played as mourners, wearing blue and white ribbons - the school's colours - to honour the former student, left the school.
  Thousands of people from his small hometown of Wyoming, Ohio, packed into Otto Warmbier's old high school for his funeral.
  For most, his casket was the first they had seen of Otto since he went to North Korea - awful confirmation of the shocking, surreal set of circumstances that had played out since early last year.
  Among several politicians in attendance, including officials from the state and defence departments was the Ohio Senator Rob Portman, who had been involved in the quest to bring him home.
  Mr Portman reflected a sense that while today was a time to talk about Mr Warmbier's life, as a young man with huge potential, the issue of responsibility had to be addressed.
  After the funeral, mourners stood to watch the cortege pass and disappear through the streets with blue and white ribbons tied to all the trees in his honour.
  As they reflect, there are many not just here but across the country, asking how North Korea will now pay for what many see as the murder of an American citizen.
  Otto Warmbier was returned by North Korea to the US last week, more than a year after he had been sentenced to 15 years' hard labour.
  He was in a coma and died a few days later. His parents say that though he never spoke or opened his eyes, "the countenance of his face changed - he was at peace. He was home and we believe he could sense that".
  US doctors say he suffered a "severe neurological injury", the most likely cause of which was a cardiopulmonary arrest that had cut the blood supply to the brain.
  A post-mortem examination was not carried out at the request of the family.
  Otto Warmbier, a student at the University of Virginia, was travelling with a tour group when he was arrested at Pyongyang airport in January 2016.
  He was accused of stealing a propaganda sign from a hotel and, two months later, was sentenced during a short trial.
  His family had no news of him until 13 June, when Pyongyang said he had been in a coma since his trial after contracting botulism and receiving a sleeping pill.
  US doctors say there is no evidence he suffered from botulism, and the Warmbier family believe he died as a result of "awful torturous mistreatment".
target: More than 2,500 family, friends and well-wishers gathered for the funeral of Otto Warmbier, the US student who died after falling into a coma while in prison in North Korea.