US President Barack Obama has issued a White House invitation to a Muslim school boy who was arrested for bringing a homemade clock to school. Ninth-grade high school student Ahmed Mohammed from Irving in Texas was arrested on Monday after his teachers reported him to the police for making a clock, which they said resembled a bomb. ?Cool clock, Ahmed. Want to bring it to the White House? We should inspire more kids like you to like science. It's what makes America great,? Obama tweeted.