A teacher from a Neath school blocked from travelling on a US-bound plane claims his name was the reason.
Juhel Miah, aged 25, had been travelling with a group from Llangatwg Community School group when he was escorted off the aircraft headed for New York at Reykjavik Airport in Iceland last month.
Hundreds of people turned out for the Stand up to Racism rally in Cardiff to lend their support.
Supporters, including Plaid Cymru leader Leanne Wood and Cardiff Central Labour MP Jo Stevens were among those who were there on the day.
Click to play Tap to play
Video will play in
Leanne Wood and Juhel Miah stand up to racism
Placard-waving campaigners from a series of different organisations were on hand to show the scale of their support.
Respected maths teacher Mr Miah, whose full name is Mohammed Juhel Miah, revealed he ran into problems after speaking to an American official ahead of getting on the flight despite travelling with a group of 39 pupils and four teachers to Iceland.
He said: “She read my first name was Mohammed and from that point onwards the problems started.”
Juhel Miah at the school where he teaches in Neath (Photo: Athena Picture Agency Ltd)
Mr Miah added: “When I was going back to get my hand luggage, as you can imagine, everyone was staring at me and they were looking at me like I was threat – as if I’d done something wrong.
“I had all the same documents as all the other teachers and all the other pupils. The only difference between them and me was, possibly, the colour of my skin, I was a Muslim and my name was Mohammed Juhel Miah.”
President Donald Trump had brought a ban into force, which led people who had travelled to seven majority Muslim countries to be blocked from travelling to the US.
Mass protests were sparked by the decision, which came into force in late January before a block was put on by a judge in Seattle.
But a second similar executive order issued by the president was blocked by federal judges on Thursday.
Mr Miah said he hhad received a letter from the US Embassy since his aborted bid to travel to the US on his first trip. The letter claimed he had never been blocked from entering the US and was free to apply for a visa to travel there in the future.
But he underlined he had clearly been barred from travelling to America even though he has a valid Electronic System for Travel Authorization (ESTA) visa at the time.
His case was flagged up in parliament by House of Commons leader David Lidington.
Ms Stevens, who spoke at the Grange Gardens event, said recent political events had exposed an “underbelly of racism” across Britain.