UN Secretary General Ban Ki-moon denounced the idea of a resort to military force over the Iran crisis, branding the notion of an attack or counter-attack as “unacceptable” and expressing concern about the “violent rhetoric” on the topic.

Ban made the comments during an interview with the French program “International” which will be broadcast Sunday, AFP reported.

He implored the sides to stick with dialogue to try to resolve the issue, and said the root of the crisis lay in Iran’s refusal to permit IAEA inspectors to visit and monitor its nuclear facilities.

The secretary general’s comments came amid ongoing speculation over a possible Israeli strike on Iranian nuclear sites. Prime Minister Benjamin Netanyahu has urged the US to set so-called “red lines” that, if crossed, would trigger a military response. The US has avoided doing so, and President Barack Obama reportedly told Netanyahu in a phone-call last Tuesday that he would not do so.

Obama has repeatedly said that an Iranian regime armed with nuclear weapons is “unacceptable” but that there is still time for diplomacy and sanctions before a possible resort to military force.

On Friday, in a conference call with American rabbis, the president said “there may come a time” that the US would “exercise a military option.”