Defense Secretary Chuck Hagel, left, escorts United Nations Secretary General Ban Ki-moon into the Pentagon as Ban Ki-moon arrives for an honor cordon, Thursday, April 18, 2013. TEL AVIV, Israel (AP) - U.S. Defense Secretary Chuck Hagel said Sunday the United States and Israel see "exactly the same" threat from Iran, but differ on when it may reach the point of requiring U.S. or Israeli military action. Hagel used his first visit to Israel as Pentagon chief to highlight his view that Israel must decide for itself whether and when to pre-emptively attack its neighbor. "Israel will make the decision that Israel must make to protect itself, to defend itself," Hagel told reporters before arriving here on Sunday to begin a week-long tour of the Middle East. Hagel acknowledged that while Israel and the U.S. share a commitment to ensuring that Iran does not acquire a nuclear weapon, there "may well be some differences" between the two allies on the question of when Iran's leaders might decide to go for a bomb. He said there is "no daylight at all" between Israel and the U.S. on the central goal of preventing a nuclear-armed Iran. But he added, "When you back down into the specifics of the timing of when and if Iran decides to pursue a nuclear weapon, there may well be some differences." Israeli Prime Minister Benjamin Netanyahu tends to see more urgency, reflecting in part the fact that certain Iranian technological advances toward a nuclear weapon could put the program beyond the ability of the Israeli military to destroy it with airstrikes. U.S. forces have greater reach. In an interview on an overnight flight from Washington, Hagel repeatedly emphasized Israel's right of self-defense and stressed that military force - by implication, Israeli or American - remains an option of last resort. "In dealing with Iran, every option must be on the table," he said. Hagel, 66, came under intense fire from Republican critics, prior to his February Senate confirmation hearing, for some of his past statements on Israel. His critics painted him as insufficiently supportive of the Jewish state. In choosing to make Israel one of his first overseas stops, Hagel sought to put that controversy behind him - with serious words and a touch of humor. The February confirmation hearing, which Republicans used to hammer him on Israel and other subjects, "was years ago," he deadpanned. During his two-day visit to Israel, Hagel is expected to put the final touches on a U.S. arms deal that would provide Israel with missiles for its fighter aircraft, plus KC-135 refueling planes that could be used in a long-range strike on a country like Iran, as well as V-22 Osprey transport planes. He called the proposed sale a "very clear signal" to Iran. "The bottom line is, Iran is a threat - a real threat," he said, not only for its nuclear ambitions and its stated goal of destroying Israel but also for its alleged sponsoring of terrorism. Hagel said U.S. and international economic sanctions are "hurting Iran significantly," but he said they do not guarantee that Iranian leaders will be persuaded to stop what the West sees as their ambition to become a nuclear power. Iran asserts that its nuclear program is designed entirely for non-military purposes. Hagel suggested he holds hope that Iran's presidential election in June might change the trajectory of its nuclear drive. He asserted that there is still time for diplomacy and international sanctions to resolve the Iran problem. "These other tracks do have some time to continue to try to influence the outcome in Iran," he said. In the interview en route to Tel Aviv, Hagel was asked whether the Obama administration has determined whether the Syrian government has used chemical weapons against opposition rebels. He said intelligences analysts are still assessing the evidence and have not reached a conclusion. After his talks in Israel, Hagel is scheduled to visit Jordan, Saudi Arabia, Egypt and the United Arab Emirates. Each of those four is an important American ally in the Middle East, and each is worried by Syria's civil war. Saudi Arabia and the UAE are part of a $10 billion proposed US arms sale that includes Israel. The UAE would get about 26 F-16 fighters and it and Saudi Arabia would get advanced air-launched missiles. U.S. Secretary of State John Kerry is also in the region. He is working to mend the strained relationship between Turkey and Israel and on Sunday he announced the White House is doubling its non-lethal assistance to the Syrian opposition to $250 million.