A US student who made a homemade clock and took it to school has been arrested after his teacher and police thought it was a bomb.

Ahmed Mohamed, 14, is a teenage inventor who makes his own radios and repairs go karts.

He hoped to impress his engineering teachers at MacArthur High in Irving, Texas, with a homemade clock he took to school on Monday in his pencil case.

Instead, the school phoned the police and he was detained and questioned.

“My hobby is to invent stuff… I made a clock and it was really easy,” the student said.

He kept the clock in his bag but the alarm beeped in the middle of an English lesson.

“She was like, it looks like a bomb. I told her ‘it doesn’t look like a bomb to me,’” he told Dallas News.

“I got arrested for a hoax bomb. An officer and the principal came and took me out and took me to a room with five officers which they interrogated me and went through my stuff and took my invention.”

Irving police spokesman James McLennan said they have no reason to think the device was dangerous.

“We have no information that he claimed it was a bomb. He kept maintaining it was a clock, but there was no broader explanation,” a police spokesman said.

Asked to clarify, the spokesman told Dallas News: “It could reasonably be mistaken as a device if left in a bathroom or under a car. The concern was, what was this thing built for? Do we take him into custody?”

“He just wants to invent good things for mankind. But because his name is Mohamed and because of September 11, I think my son got mistreated,” the student’s father, Mohamed Elhassan Mohamed said.