for analysis on both sides, i've been speaking to bbc persian‘s bahman kalbasi and barbara plett usherrst here's barbara on what evidence the us has to back up its claims. that list of things he mentioned, intelligence, previous attacks and type of weapons used and so on, so it is assessment by the united states but he is the only one that has come out so far and made a definitive statement about this attack or frankly the previous one that took place a few weeks earlier against four tankers off of the united arab emirates. there, the us also said it was almost certain that it was iran where as other parties did not make that definitive claim. it is interesting, the incident then and today to show how easy it is really to disrupt the oil flow through the gulf and to disrupt global oil prices. so one would've thought this might be a limitation of the maximum pressure campaign that the us has been opposing on iran. if it indeed is iran and responding in this way. but mr pompeo said they showed the sanctions that iran did not have a right to respond to economic sanctions by targeting oil