"As I was making my way out of the plane I looked back at the kids to tell them everything was going to be okay. The look I got off the kids, they were shocked, they couldn't believe what was happening. This is when I felt like I was a criminal," Juhel Miah, a math teacher at Llangatwg Comprehensive School in Wales told CNN.
Miah, 25, was one of four school staff accompanying the children, aged 12-15, on a trip to New York, that included a one-night stopover in Reykjavik, Iceland.
Miah, who is Muslim, was born in Birmingham, England, and grew up in Swansea, Wales. The trip was due to be his first visit to the US. He was traveling on his British passport with a US visitor's visa, he told CNN. Miah is not a citizen of any other country.
'Ticked all the right boxes'
"It all started when I met the first official. I gave her my passport. My first name is Mohammad. Straight away she looked at me and said you have been randomly selected for a security check," Miah told CNN.
After a brief search, Miah was allowed to board the plane. But shortly after that, he was informed he had been denied entry to the US and wouldn't be able to travel.
"I asked her on what ground was I denied access. I got my ESTA [US visitor's] visa, I have a British passport, I ticked all the rights boxes. She did not give me an answer," he said.
Icelandair told CNN, "We refused carriage to Mr. Miah based on a recommendation from the US Customs and Border Protection Agency and line with our conditions of carriage."
The school trip proceeded but the teacher's removal from the flight left students "shocked and distressed," the school district said in a statement. The students, aged 12-15, returned from the US on Monday.
Miah returned to the United Kingdom the following day.
'Act of discrimination'
In a letter to British Foreign Secretary Boris Johnson, Carwyn Jones, the First Minister of Wales, said the incident appeared to be "an act of discrimination against a UK passport holder, and asked Johnson to seek an explanation from US authorities.
Jones said the incident appeared to contradict Foreign Office advice for UK citizens traveling to the US
, and statements made by Johnson.
Days after President Donald Trump's executive order travel ban was signed on January 27, Johnson told the House of Commons, "We have received assurances from the U.S. Embassy that this executive order will make no difference to any British passport holder, irrespective of their country of birth or whether they hold another passport."
The British Foreign Office said in a statement provided to CNN, "We are providing support to a British man who was prevented from boarding a flight in Reykjavik," but did not provide further details.
The Muslim Council of Wales said it was "deeply troubled" by the incident.
CNN has reached out to US Customs and Border Patrol (CBP) for more information.