Bomb-plot teenager 'planned spectacular show of terrorism'

Somali-born US citizen Mohamed Osman Mohamed, 19, was arrested on Friday in Portland, Oregon, after using a mobile phone to try to detonate what he thought were explosives in a van, prosecutors said.

But it was a dummy bomb put together by FBI agents and authorities said the public was never in danger.

Mohamed will appear in court today, charged with attempted use of a weapon of mass destruction, which carries a maximum sentence of life in prison.

He believed he was receiving help from a larger ring of jihadists as he communicated with undercover agents, a law enforcement source said.

The official said Mohamed was committed to the plot and planned the details alone, including where to park the van in order to hurt the most people.

"I want whoever is attending that event to leave, to leave dead or injured," Mohamed said, according to the affidavit. "It's in Oregon, and Oregon, like you know, nobody ever thinks about it," the suspect told an agent in one discussion.

Thousands had gathered on a cold, clear night for the annual Christmas tree lighting event at Pioneer Courthouse Square, a plaza often referred to as "Portland's living room" because of its popularity.

The ceremony began just 10 minutes before Mohamed's 5.40pm arrest. Babies sat on shoulders and children cheered at the first appearance of Santa Claus.

The tree-lighting on the bricks of the plaza went off without a hitch just as the arrest was taking place.

Mohamed, who grew up in Beaverton, is a former Oregon State University student, and was enrolled in courses from late 2009 until October 6 before withdrawing, said Oregon State University spokesman Todd Simmons.

The law-enforcement source said agents began investigating Mohamed after receiving a tip from someone concerned about him.

The FBI monitored Mohamed's e-mail and found he was in contact with people overseas, asking how he could travel to Pakistan and join the fight for jihad, according to an FBI affidavit.

The law enforcement official said Mohamed e-mailed a friend living in Pakistan who had been a student in Oregon in 2007-2008 and had been in Yemen as well.

The e-mails led the FBI to believe Mohamed's friend in Pakistan "had joined others involved in terrorist activities" and was inviting Mohamed to join him