President Donald Trump told Gulf leaders in New York on Tuesday that the US was seeing little activity at Iran’s Pickaxe Mountain nuclear site near Natanz, while threatening an immediate strike if activity resumes. “We may have to blow up another one, Pickaxe Mountain. We’re not seeing a lot of activity there, but if we do, we’ll blow it up immediately,” he said.

At the meeting on the sidelines of the UN General Assembly, Trump said Washington was increasing financial pressure on Tehran. “We’re completely isolating Iran financially,” he said, urging Iran to act before it was too late. Earlier in his General Assembly address, he called on other nations to economically isolate Iran and predicted a deal after November’s US midterm elections.

Iran has offered to reopen the Strait of Hormuz within seven days if the US eases military pressure and lifts its blockade of Iranian ports, a senior Iranian official told Reuters on Tuesday. The proposal reached Washington through mediators on Sept. 16, and Iran’s delegation in New York has authority to revive diplomacy, the official said. Secretary of State Marco Rubio said the US was open to meeting Iranian officials at the UN, but nothing was scheduled.