Prosecutors have made their last effort to convince a 16-person jury that a teenager was predisposed to terrorism when undercover FBI agents posing as members of Al Qaeda helped him devise a plot to detonate a bomb.

Assistant U.S. Attorney Ethan Knight said Wednesday in closing arguments that Mohamed Mohamud was predisposed to terrorism when he was 15 years old, the age he told undercover agents he began to think about committing violent jihad.

Knight says jurors may disagree with the FBI's methods in its undercover sting operation, but they cannot argue that Mohamud intended to kill thousands at Portland's 2010 Christmas tree-lighting.

Mohamud's trial on terrorism charges began Jan. 10.

His defense attorneys will make closing arguments Wednesday afternoon. They contend he was entrapped by the FBI.