serious because they are not only decided to assassinate someone, they have taken on the very basis in which nations deal with one another. reporter: 56-year-old monssur arbabsiar is being held, the plan was to hire a during cartel to carry out the assassination using explosives. the u.s. is busy contacting allies to present the united front against iran. we will be consulting with our friends and partners around the world about how we can send a very strong message that this kind of action which violates international norms must be ended. reporter: now, the u.s. and the world will probably try to impose further sanctions on iran but vice president biden said this morning nothing is off the table, and we have this statement from the white house, it says the president was first briefed on the issue in june and directed his administration to provide all necessary support to this investigation. the disruption of this plot is a significant achievement by our intelligence an