JERUSALEM, Jan. 22 (Xinhua) -- Israeli Foreign Minister Tzipi Livni and new U.S. Secretary of State Hillary Clinton Thursday agreed to maintain close cooperation on Iran's nuclear issue, local daily Ha'aretz reported on its website.

    Shortly after Clinton officially took the helm at the U.S. State Department on Thursday, Livni and Clinton had a phone conversation and agreed to cooperate closely on the issue of Iran's nuclear program.

    The two also agreed to work together in order to exert more pressure on Tehran, according to Ha'aretz.

    The United States and Israel have been accusing Iran of developing secretly nuclear weapons under the cover of civil nuclear program. Iran denies the charges.

    Turning to situation in the Hamas-ruled Gaza Strip, Livni told Clinton that Israel is involved in humanitarian efforts to reconstruct the Palestinian coastal enclave, which has been ravaged by Israeli army's 22-day Cast Lead Operation.

    The foreign minister said that Israel strongly opposes Hamas receiving a leading role in those efforts, adding that the international community must not grant Hamas any legitimacy.

    "Hamas is the enemy of peace in the region," said Livni, "It threatens anyone who wants quiet in the Middle East."

    Also on Thursday, Israeli Prime Minister Ehud Olmert had a phone conversation with Clinton and congratulated her on assuming her important and central office.

    According to a statement released by Olmert's office, Olmert told Clinton that Israel is interested in continuing to advance the Middle East peace process and intends to invest great effort in providing humanitarian assistance to Gaza residents.

    Israel would also do its utmost in order to fight terrorism and prevent weapons from being smuggled to the militant groups in Gaza, vowed the premier.

    Earlier Thursday, Clinton, who arrived at the U.S. State Department for her first full day as secretary of state, promised a new era in U.S. diplomacy but tough times ahead.