Donald Trump has attacked the "brutality of the North Korean regime" following the death of American student Otto Warmbier - who had been imprisoned in the country for 17 months.

The US President has offered the family of Mr Warmbier his respects after news broke that the young man had died after being transported back to the United States from North Korea.

“Melania and I offer our deepest condolences to the family of Otto Warmbier on his untimely passing,” Mr Trump said in a statement. “There is nothing more tragic for a parent than to lose a child in the prime of life. Our thoughts and prayers are with Otto’s family and friends, and all who loved him.”

The President proceeded to say that Mr Warmbier’s untimely death recommitted his administration to make sure that another tragedy like the one that surrounded Mr Warmbier would not happen again.

“The United States once again condemns the brutality of the North Korean regime as we mourn its latest victim”, he said.

Mr Warmbier was imprisoned in a North Korean jail last year, eventually sentenced to 15 years of hard labour for allegedly attempting to steal a North Korean propaganda banner. He was handed over to US officials and flown back to America last week having been in a coma shortly after his March 2016 jailing.

The 22-year-old has been described as a bright, enthusiastic, and adventurous young man. The University of Virginia student was planning on spending his third year of college in China, which is how he found out about the Chinese tour companies that bring Americans on trips to see North Korea. His parents had thought the idea was okay at the time.

North Korean officials have indicated that he went into the coma after getting botulism, and taking a sleeping pill. The family has indicated that they doubt the veracity of that claim. Doctors who examined Mr Warmbier after his release said there was no sign of botulism in his system.

Physicians said last Thursday that Mr Warmbier had shown no sign of understanding language or of awareness of his surroundings, and had made no “purposeful movements or behaviors.”

The circumstances of his detention in North Korea, and what medical treatment he received there, remained a mystery. But relatives have said his condition suggests he was physically abused by his captors.

“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,” the family said in a statement following Mr Warmbier's death.

The University of Virginia student's father, Fred Warmbier, said last week that his son had been “brutalised and terrorised by the Pyongyang government

Mr Warmbier was freed after the US State Department's special envoy on North Korea, Joseph Yun, traveled to Pyongyang and demanded the student's release on humanitarian grounds, capping a flurry of secret diplomatic contacts, a U.S. official said last week.

Tensions between the United States and North Korea have been heightened by dozens of North Korean missile launches and two nuclear bomb tests since the beginning of last year. Pyongyang has also vowed to develop a nuclear-tipped intercontinental ballistic missile capable of hitting the US mainland.

Susan Thornton, the US acting assistant secretary of state for East Asia, said earlier on Monday that the United States was concerned for the welfare of the three other US citizens still held in North Korea - Korean-Americans Tony Kim, Kim Dong Chul and Kim Hak Song.

Responding to the death of Mr Warmbier, US Secretary of State Rex Tillerson said: “We hold North Korea accountable for Otto Warmbier’s unjust imprisonment, and demand the release of three other Americans who have been illegally detained.”