The Strait of Hormuz will remain closed until the US changes its behaviour and accepts Iran’s conditions for ending the war, Iran’s newly appointed secretary of the Supreme National Security Council Mohsen Rezaei said on Tuesday, signalling that any agreement over the waterway would not automatically restore shipping.

“As long as America does not change its behaviour and does not accept Iran’s conditions, the Strait of Hormuz will not be opened,” Rezaei was quoted as saying by the semi official Tasnim news agency.

He said Iran’s conditions included an end to the war, the release of its frozen assets and an end to fighting across the region, including in Lebanon and Gaza.

Rezaei said any agreement reached between Iran and Oman over a transit route through the strait would be separate from the decision to reopen the waterway.

His comments came after he was appointed on Sunday as second in command of the body responsible for coordinating Iran’s security and foreign policy. He said Iran’s conditions had been conveyed to the US through mediators.

Mohammad Mokhber, an adviser to Supreme Leader Ayatollah Mojtaba Khamenei, also said on Tuesday that Iran’s response to the conflict would continue and that the strait would remain closed until its conditions were met.

Oil futures extended their gains as uncertainty grew over the future of the waterway, through which around a fifth of global oil and liquefied natural gas supplies passed before the war.

There was no immediate response from Washington to the latest Iranian statements. US President Donald Trump has demanded compensation from Iran for people killed in wars, attacks and protests and accused Tehran of being “devious negotiators”.

“We’re going to ask for money for the damage they’ve done over a 50 year period,” Trump said on Monday.

Pakistan, one of the main mediators alongside Qatar, had earlier raised hopes of progress in negotiations. Pakistani Defence Minister Khawaja Asif said the two sides appeared to be “close to some sort of an arrangement”.

The conflict has also continued to disrupt shipping. Four crew members were reported killed in a suspected attack by Yemen’s Iran backed Houthis on a cargo vessel in the Bab el Mandeb Strait on Tuesday, while a container ship was reportedly struck by a missile off Pakistan in a suspected US attack.

The developments have added to concerns over maritime security in the Gulf of Oman, the Red Sea and surrounding waterways.