TEHRAN - Iran’s supreme leader Ayatollah Ali Khamenei said on Tuesday that flexibility was sometimes necessary in diplomacy as his negotiators prepared for new talks on his government’s controversial nuclear drive.

Khamenei’s comments, reported by state television, came after Iran’s moderate new President Hassan Rowhani, who took office last month, said he would show flexibility in renewed talks with the major powers. “Heroic flexibility is very useful and necessary sometimes but with adherence to one main condition,” Khamenei told members of the elite Revolutionary Guards.

“A wrestler sometimes shows flexibility for technical reasons. But he does not forget about his opponent nor about his main objective,” Khamenei said.

On Sept 11, Rowhani said he had the tacit support of Khamenei for “flexibility” in talks with six major powers that are expected to resume in the coming weeks. Rowhani has said he wants to allay Western concerns but that he will not renounce Iran’s goal of an independent civil nuclear programme. Foreign Minister Mohammad Javad Zarif was to fly to NY later on Tuesday to attend the UNGA. On the sidelines, he is scheduled to meet the EU’s top diplomat, Catherine Ashton, who represents the powers in the decade-long talks. Iran’s foreign ministry spokeswoman Marzieh Afkham on Tuesday strongly criticised Obama’s position. “It is a source of regret that he still uses the language of threat after we told them to replace it with one of respect,” Afkham told reporters.

In an earlier statement, she said it was “unjustifiable” that the White House should “violate international rules and the UN charter to cater to the interests of lobbies by resorting to the military option.” In the ABC interview, Obama also revealed that he and his Iranian counterpart had exchanged letters. Afkham confirmed that an exchange of letters had taken place “through diplomatic channels,” without going into details.

Tehran and Washington have had no diplomatic relations since the aftermath of Iran’s 1979 Islamic revolution when US embassy staff were held hostage.

Meanwhile, Israeli Prime Minister Benjamin Netanyahu said on Tuesday he would stress the need to halt Iran’s nuclear programme when he meets US President Barack Obama later this month.

Speaking at a meeting of his cabinet, Netanyahu said he would meet Obama before addressing the United Nations in New York.

“In another week-and-a-half or so I will travel to the UN General Assembly. I will first meet with US President Barack Obama,” a statement from Netanyahu’s office quoted him as saying.

“I intend to focus on the issue of stopping Iran’s nuclear programme,” he said, laying out four steps that Iran must take: halting all uranium enrichment, removing all enriched uranium from its territory, closing its underground nuclear facility in Qom and halting construction of a plutonium reactor.