The death in the US of "nearly blind" refugee Nurul Amin Shah Alam, who was found outdoors in freezing temperatures days after his release from federal immigration custody, has been ruled a homicide in New York state.

The Erie County Medical Examiner's Office said Shah Alam's death in the city of Buffalo was caused by "complications of a perforated duodenal ulcer, precipitated by hypothermia and dehydration".

The designation of homicide may include negligent acts or omissions, the local officials said. It does not imply intent to cause harm or death, or indicate criminality.

In response, a US Customs and Border Protection (CBP) spokesperson told the BBC it was "another hoax being peddled by the media and sanctuary politicians to demonize our law enforcement."

"This death had NOTHING to do with Border Patrol," the spokesperson said in a statement, adding Shah Alam died almost a week after he was released by Border Patrol.