Chicago (AFP) - The Muslim teenager arrested when a teacher mistook his homemade clock for a bomb threatened to sue his school and the town of Irving, Texas for $15 million, his lawyer said.

Ahmed Mohamed, 14, became an overnight sensation in September after his sister tweeted a photo of the aspiring inventor standing in handcuffs while wearing a t-shirt with the US space agency NASA's logo.

President Barack Obama joined a surge of public support by congratulating the teen on his skills and inviting him to bring the clock to the White House in what was seen as a pointed rebuke to school and police officials amid accusations of Islamophobia.

Invitations poured in from Facebook, Google, the United Nations and Mohamed later tweeted photos of visits to Mecca, New York, Sudan and Qatar.

But his lawyer insists there was a dark side to his fame, which caused "severe psychological trauma," according to a letter notifying the city and school district of his demands.

The son of Sudanese immigrants who lived in a Dallas suburb, the young robotics fan brought in a homemade clock to impress a new teacher at MacArthur High School.

Instead, Mohamed was accused of trying to scare people with a hoax bomb and escorted from the school in handcuffs.

His lawyers insist that the school, police force and city officials violated Mohamed's rights by wrongfully accusing and detaining him and then decided to "trash" him when the media got wind of the story.

"Ahmed clearly was singled out because of his race, national origin and religion," attorney Kelly Hollingsworth wrote.

The letter noted that Irving Mayor Beth Van Duyne called the clock a "hoax bomb" during an appearance on the Glenn Beck television show and nodded as Beck and his other guest called the story "an influence operation" in furtherance of a coming "civilization jihad."

"Not only was this dangerous 'baiting' that destroyed any chance the Mohamed family ever had of being truly safe and secure in the United States, but it was also defamatory," his lawyers wrote.

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The family received threatening emails and left their home after their address was publicized.

They eventually moved to Qatar after Mohamed was offered a generous scholarship.

His attorneys are seeking $5 million in damages from the school district and $10 million from the city of Irving and said they will file a civil suit if they do not receive a reply within 60 days.