The dividing opinion between Europe and US on the matter is plain for all to see
European leaders have been shy in attributing the attacks to Iran, a sort of similar stance seen in the whole nuclear deal debacle, but the US is continuing to make clear that Iran is responsible for the attacks on Saudi Arabia over the weekend.
Yesterday, the US said that they could pinpoint the exact location the attacks came from and they noted that it stemmed from the southwest of Iran.
If anything else, this just shows how much of a fine line Europe has to walk on in terms of managing geopolitical relations and it doesn't look like they'll be able to persuade either Rouhani or Trump to the negotiating table any time soon.