The climate has turned gloomy around world powers’ talks with Iran to revive a frayed nuclear accord, as a new ultraconservative Iranian president formally takes over and a crisis in Persian Gulf shipping lanes threatens to deepen.

Cleric Ebrahim Raisi was sworn-in before dozens of officials in a ceremony in Iran’s parliament on Thursday. Iran had put the brakes on nearly three months of nuclear talks in Vienna to allow for its June presidential election and the changing of the guard, and hasn’t signaled when negotiations might resume.

The talks are intended to rein in Iran’s nuclear work in exchange for sanctions relief that would allow it to return to global oil markets. The delay has already put off Iran’s oil comeback beyond what many traders expected.