WASHINGTON ( CNN ) -- President Barack Obama weighed in Thursday on the conflict between Israel and Hamas , urging Israel to open Gaza border crossings and telling the Islamic fundamentalist organization to stop rocket fire into the Jewish state . President Obama called on both Israel and Hamas to make changes toward Mideast peace . He urged Israel to allow the flow of aid and commerce into the Palestinian territory . `` Our hearts go out to Palestinian civilians who are in need of immediate food , clean water and basic medical care , '' he said . The crossings should be opened with an `` appropriate monitoring , '' he added . Obama said Hamas leaders , for their part , must put an end to rocket attacks . He said he will send former Sen. George Mitchell , who was appointed Thursday as special envoy for Middle East peace , to the region as soon as possible . Earlier , Secretary of State Hillary Clinton arrived at her new office in the State Department , promising a renewed emphasis on candor and `` robust diplomacy '' as the primary means for advancing American interests around the world . America 's new chief diplomat walked through the front doors of the State Department lobby shortly after 9 a.m . ET to thunderous applause from an overflow crowd of about 1,000 career diplomats and other department employees . `` I believe with all of my heart that this is a new era for America , '' Clinton told her colleagues . `` President Obama set the tone with his inaugural address . ... Robust diplomacy and effective development are the best long-term tools for securing America 's future . '' Watch Clinton greet her new employees » . In remarks that could be interpreted as a rebuke of the departed Bush administration , Clinton also said that the Obama administration would not `` tolerate the divisiveness and paralysis that has undermined our ability to get things done for America . '' Clinton also called for a new sense of candor and free exchange of ideas . She urged the country 's diplomatic corps to think `` outside the proverbial box . '' `` There 's nothing I welcome more than a good debate and the kind of dialogue that will make us better , '' she said . Clinton later attended an intelligence briefing and a meeting with members of the Diplomatic Security Service . She also walked through various State Department offices , including the operations center . Clinton also phoned international leaders , according to acting State Department spokesman Robert Wood . She is expected to call Asian leaders later Thursday . Clinton will also visit the U.S. Agency for International Development , which she praised `` for the work they 've done on behalf of development through some very difficult years . '' During her confirmation hearing , Clinton pledged to secure more resources for the State Department and USAID , which has seen a lot of its development work fall to the Pentagon during the Bush administration . Clinton is the 67th U.S. secretary of state . CNN 's Elise Labott contributed to this report .
NEW : President Obama urges Israel to open Gaza border crossings . The U.S. president said he was "encouraged" by Israel's decision to allow the passage of humanitarian aid into Gaza. Clinton greets employees at the State Department . Clinton was confirmed as secretary of state Wednesday .