Israeli Prime Minister Benjamin Netanyahu on Monday met with U.S. President Barack Obama in their ninth and likely most significant meeting between the two.

"This is one of the most important meetings that an Israeli prime minster will ever have in Washington because this will determine whether or not Israel is going to use force against Iran or not," Prof. Eytan Gilboa of Bar-Ilan University told Xinhua prior to the meeting.

"What Obama wants is a commitment from Israel not to use force, at least until after the presidential elections in November. Israel wants from the United States that it fulfills its commitment to prevent Iran from becoming a nuclear power," he added.

CONCERNS FOR NUCLEAR IRAN

In parallel, earlier that day at a press conference of the International Atomic Energy Agency (IAEA), director Yukiya Amano said that the United Nations nuclear watchdog had serious concerns about the military aspect of Iran's nuclear program.

Back at the White House, before meeting with Obama, Netanyahu said that Israel must be able to defend itself "by itself" against any possible threat and that the two allies must stand together on the Iran issue.

Obama replied that the United States "will always have Israel's back," and that it's in the best interests of the United States to prevent a nuclear Iran.

"Netanyahu says that Israel has to defend itself, and Obama said that the United States doesn't exclude military options, but this is not the right time" to apply them, according to Dr. Ephraim Kam of the Institute for National Security Studies at Tel Aviv University.

"We have to exhaust the diplomatic course with the sanctions, and then see what happens," Kam said, adding that "This is the bottom line and the difference between the two leaders."

While Israel and the United States agree that Iran shouldn't be allowed to develop a nuclear weapon, there are differences regarding both the use of a military strike against the program, and whether or not Iran has taken a final decision to actually build a nuclear bomb or just prepare the parts.

DIFFERENT TIME SCHEME

Iran's relocation of its nuclear material to an underground facility near the city of Qom in southeast Iran has been mentioned as a possible "red-line" for Israel, beyond which it would need to take military action.

However, due to the substantially superior military capabilities of the Americans, it is believed that Washington prefers to wait until a nuclear weapon has been constructed before actually taking military action.

There have been a number of reports over the last couple of years covering possible scenarios for an Israeli attack on Iran's nuclear infrastructure, and most agree that Israel currently lacks the capability to comprehensively conduct such an operation.

Both Israel and the United States believe that even a successful attack on Iran's nuclear facilities would result in counter attacks targeting Israel itself and U.S. troops and interests in the Middle East.

The European Union recently imposed tougher economic sanctions on Iran targeting both the banking and the oil export sectors.

The United States has already imposed a ban on import of Iranian oil, and has asked both Japan in India to follow the European initiative, but so far there has been no formal reply.

While Netanyahu is supportive of the sanctions, he argues that the military option needs to be kept "on the table," since Israel believes that a nuclear Iran poses an existential threat, not only due to a possible nuclear attack but also via the added deterrence Iran could provide to its regional allies, including Hamas in Gaza and Hezbollah in Lebanon.

QUESTIONS FOR THE MEETING

Gilboa said that during the meeting Netanyahu is likely to ask Obama what he would do if the sanctions fails, noting that for the sanctions to be successful the United States would need more cooperation with major players like Russia and China.

"This is unprecedented: Israel has never asked the United States for permission to use force, and the United States has never given Israel permission to use force - so if the United States now says that Israel needs to tell them before you attack Iran - this is unprecedented," Gilboa said.

"And I don't know if the prime minister will give this kind of commitment given the sensitivity of the issue," he concluded.