President Shimon Peres flew out to the US in the early hours of Sunday morning for a four-day diplomatic visit. Peres will meet US President Barack Obama, Vice President Joseph Biden, Secretary of State Hillary Clinton and UN Secretary-General Ban Ki-moon. The president's meeting with Obama - the first formal talks between the new US leader and an Israeli official - is expected to focus on the global effort to thwart Iran's nuclear program, the peace process with the Palestinians and the issue of captured IDF soldier Gilad Schalit. "The government is currently undergoing a policy review and we need to wait until it's complete," Peres told Army Radio. "I will update Obama on the developments, but the main thing that unfortunately cannot be ignored is Iran, which is trying to gain control of the region." The president's office stated that Peres would also use his visit to embark on a broad campaign of public diplomacy on behalf of Israel. His office said he would grant a number of interviews to television, radio, and print magazines, including Vanity Fair, The Atlantic, Rolling Stone, National Public Radio, Wolf Blitzer on CNN and Joe Scarborough's Morning Joe program on MSNBC. Opposition leader Tzipi Livni also headed Sunday to the US, where she is set to meet Clinton and National Security Adviser Gen. James Jones. She and Peres will also both address the AIPAC conference. In an interview with Army Radio on Sunday morning, Livni criticized Prime Minister Binyamin Netanyahu, who is set to meet the US president in Washington on May 18, saying, "In my opinion, it's problematic that the government still has no proper plan to present to the Americans." Livni added that taking the two-state solution off the table would pose a strategic risk to Israel. "I have still not been convinced of the will on the part of the new government to move ahead with this solution," she said. "I had a meeting with Netanyahu during which I clarified my position I intend to present in my meetings in the US, including the need to stop Iran's nuclear program and to fight terror," she continued. "I don't believe in dialogue with Hamas when it's still on its aggressive course, so negotiations must be conducted with the moderates." The Likud dismissed Livni's criticism, saying in a statement, "In stark contrast to the Kadima government that held talks with the Palestinians and got nothing in return, the Likud will conduct negotiations in order to reach real peace." The statement went on to say that a basic condition for resuming peace talks was Palestinian recognition of Israel as a Jewish state, something it said Kadima "did not stick to, just like it didn't stick to anything." Meanwhile, Foreign Minister Avigdor Lieberman will head to Europe this week for a series of meetings. Lieberman will hold talks in Rome with Italian Prime Minister Silvio Berlusconi before flying to the capitals of France, the Czech Republic and Germany to meet with his counterparts for discussions on recent calls to freeze plans to upgrade ties between the European Union and Jerusalem.