Iran’s supreme leader has dismissed initial offers being made at talks in Vienna aimed at saving Tehran’s tattered nuclear deal with world powers.

He described them as “not worth looking at” after an attack on an atomic site in his country.

The comments by Ayatollah Ali Khamenei, who has the final say on all matters of state in the Islamic Republic, come as informal talks in Vienna continue ahead of a planned formal round of negotiations.

The talks have already been thrown into disarray by a weekend attack on Iran’s main nuclear enrichment site suspected to have been carried out by Israel.

Tehran retaliated by announcing it would enrich uranium up to 60%.

“The offers they provide are usually arrogant and humiliating (and) are not worth looking at,” Ayatollah Khamenei said in an address marking the first day of Ramadan in Iran.

While saying he remained positive about Iran’s negotiators, he criticised the US and warned time could be running out.

“The talks shouldn’t become talks of attrition,” Ayatollah Khamenei said.

“They shouldn’t be in a way that parties drag on and prolong the talks. This is harmful to the country.”