Iran bought five weeks for its nuclear program through talks with the P5+1 group of world powers, Defense Minister Ehud Barak said in an interview with CNN's Kristiana Amanpour on Thursday. The first round of talks between Iran and the five permanent members of the UN Security Council plus Germany took place last weekend in Istanbul, with a second round of talks scheduled for May 23 in Baghdad.Barak spoke prior to a meeting with US Secretary of Defense Leon Panetta and US Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey in Washington. During that meeting, which lasted over an hour, the officials discussed a wide range of issues, including Iran, Syria, US aid to Israel, maintaining Israel's qualitative edge in the region, and the Iron Dome missile-defense system. "I am realistic enough to not be so optimistic about talks with Iran," he said. "The Iranians have a history of deceiving the world, sometime through steps like this. So we are a little bit skeptical."Barak mentioned a Muslim notion called takkiya, which he said grants Muslims the right to lie in order to deceive non-Muslims, for the sake of the religion."It is clear that the Iranians are focused on reaching nuclear capability, and they are ready to defy and deceive the whole world," he said.Asked if he believed the sanctions promoted by the international community will be enough to avert a military strike on Iran's nuclear facilities, Barak stated that "the sanctions are quite effective, but are far away from working." He added that Iranian Supreme Leader Ayatollah Ali Khomenei had probably not yet given the order to start actually building a nuclear bomb, but said that this was only because they feared this would lead to a military strike. Barak said that if Iran were to stop enriching uranium past 20%, move their 20% enriched uranium to a friendly country, and decommission their installation in Qom, and agree to IAEA conditions, Israel would be satisfied. "This should be the threshold (for negotiations)," he said. "If this threshold is not set at the opening of negotiations, they will never be met."Barak threatened that "all options are on the table" when asked whether or not there was a possibility that Israel could strike Iranian facilities before the start of the next round of talks, set to take place in Baghdad."It will be extremely more complicated, it will be extremely more dangerous... to deal with Iran once it goes nuclear," he said. "It happened already with North Korea, it happened with Pakistan."Asked if Israel would inform the US if it decides to attack Iran, Barak said "we have very open, frank conversations with the US about these kinds of things... We do whatever is reasonable." "I don't want to implicate the United States, I don't want to drag the United States into anything," he added, saying that there is no difference in Israeli and US intelligence assessments of Iran.Turning to Syria, Barak had some harsh words for President Bashar Assad. "What is happening there is a tragedy, it's a crime. They are slaughtering their people there by the day," he said, adding that the international community should take action, including sanctions, to stop this. "Anything from providing them with weapons to creating safe areas along the borders" for citizens, Barak said. Barak singled out the Russians and the Chinese for the failure of the United Nations Security Council to take effective action against Assad."Assad's fall would be a major blow to Iran... it would weaken dramatically both Hezbollah in Lebanon and Hamas and Islamic Jihad in Gaza. It would be very positive," Barak said.