A senior Israeli official said Sunday that sanctions on Iran should be increased to pressure Tehran to end its suspect nuclear program, despite the election of a reformist-backed president, as nuclear efforts remain firmly in the hands of ruling clerics.

Yuval Steinitz, Israel's minister of intelligence and strategic affairs, spoke to Army Radio a day after the surprise victory by Hasan Rowhani in Iran's presidential election was announced.

Although Rowhani is considered as a relative moderate and had the backing of Iranian reformists, Supreme Leader Ayatollah Ali Khamenei is the ultimate authority on all state matters and key security policy decisions — including nuclear efforts, defense and foreign affairs — remain solidly in the hands of the ruling clerics and their powerful protectors, the Revolutionary Guard.

"It's good to see the Iranian people protest against the radical regime," Steinitz said. But he cautioned, "As long as we don't see a change it's better to be wary and not celebrate prematurely."

Steinitz is close to Israeli Prime Minister Benjamin Netanyahu and is responsible for monitoring Iran's nuclear program.

He said he doubted that the election of the new president will soften Iran's stance in its nuclear standoff with the west. "Therefore the international community needs to work hard to tighten sanctions and present a clear ultimatum to Iran in order to maybe bring about change," Steinitz said.

"The Iranians today are very close to the red line, they are about a year or less to a first (nuclear) bomb," he said.

Israel considers a nuclear-armed Iran to be an existential threat, citing Iranian calls for Israel's destruction, its support for anti-Israel militant groups and its missile and nuclear technology.

Tehran insists its nuclear program is peaceful, a claim that Israel and many Western countries reject.

Israel has said that it prefers diplomacy and sanctions to end Iran's nuclear program but has hinted that military action would be an option if other peaceful attempts fail. It has called on the international community to issue a clear ultimatum to Iran to curb its nuclear program.

Meir Litvak, head of Iranian studies at Tel Aviv university, told Army Radio that Rowhani's "smiley face to the west" might make the option of military action harder.

Rowhani's predecessor Mahmoud Ahmadinejad on multiple occasions made references to the destruction of the Jewish state.