Iran’s supreme leader, Ayatollah Ali Khamenei, delivered a lengthy, sweeping speech at the country’s holiest site Thursday in which he suggested that he is open to nuclear talks, if not optimistic about their outcome.

A day after Iran celebrated its new year, Khamenei, speaking at the shrine of Imam Reza in Mashhad, the country’s second-largest city and his home town, covered a range of issues he deemed essential for Iran to address in the coming year, including the effect of sanctions, the country’s over-reliance on oil revenue, the possibility of negotiations with the United States and the upcoming Iranian presidential election.

In his remarks, which were broadcast live on state television, Khamenei also issued a warning to Israel’s leaders. “At times, the officials of the Zionist regime threaten to launch a military invasion,” he said. “But they themselves know that if they make the slightest mistake, the Islamic republic will raze Tel Aviv and Haifa to the ground.”

Alluding to U.S.-led economic sanctions on Iran, Khamenei said that “the enemies’ efforts to isolate us have failed completely,” though he acknowledged that sanctions targeting the country’s vital oil sector and its ability to conduct international bank transactions have done harm.

Despite his defiant tone, Khamenei hinted at a possible break in Iran’s diplomatic impasse with the United States and other Western powers over his country’s refusal to halt its uranium-enrichment activities.

“I am not optimistic about talks with the U.S., but I’m not opposed to them, either,” Khamenei said, but he added that the United States must prove that negotiations are not simply “a tactic designed to deceive public opinion.”

He also said that, in his opinion, the United States “doesn’t want the nuclear conflict to end.”

“If they want it to end, the solution is easy and within reach,” he said, adding that Iran had followed the rules laid out by the International Atomic Energy Agency and would continue to do so.

Khamenei spent the final portion of the nearly 90-minute-long speech discussing the importance of the presidential vote, scheduled for June. “All political groups that believe in the Islamic republic must take part,” he said.

Although Khamenei was previously supportive of outgoing President Mahmoud Ahmadinejad, a political rift has developed between them over the past two years, with Ahmadinejad at times publicly defying the more powerful Khamenei.

In a jab at Ahmadinejad, Khamenei said, “The next president must have all the strong points of the current president without any of his weaknesses.”