President Donald Trump threatened “severe bombing” of Oman if it obstructs a prospective US agreement with Iran over the Strait of Hormuz, according to an August 18 report. Trump also urged Tehran to surrender as the conflict, which began on February 28, approaches six months. Iran has effectively kept the strait closed since the conflict started, the report said.

Speaking to Fox News journalist Trey Yingst, Trump said Oman would be bombed if it stood in the way. Oman, a US ally in the Gulf, made no public response. Tehran and Muscat have been discussing future shipping arrangements for several weeks, and Iran’s Foreign Ministry said Monday that both sides were working on a joint declaration.

The talks began after a Pakistan-mediated attempt at an interim US-Iran agreement on keeping shipping normal failed. Shipping through the strait has fallen sharply, though Trump has repeatedly claimed the United States controls Hormuz. The conflict and energy-price volatility have increased pressure on Republicans before November’s midterm elections. Turkish President Recep Tayyip Erdogan stressed the need to use diplomacy fully to reduce tensions.