Calling for border crossings into Gaza to be opened with "appropriate monitoring" to alleviate the humanitarian problems following Operation Cast Lead, US President Barack Obama declared on Thursday his intention to pursue peace between Israelis and Palestinians. To that end, he announced during his first visit to the State Department that new envoy George Mitchell would soon be dispatched to the region to help ensure the cease-fire holds and to move forward on working with Israelis and Palestinians. "Let me be clear: America is committed to Israel's security. And we will always support Israel's right to defend itself against legitimate threats," Obama said. "No democracy can tolerate such danger to its people, nor should the international community, and neither should the Palestinian people themselves." He praised Egypt's role in helping to end the violence, and indicated that America would be committed to ending arms smuggling into the Gaza Strip. "Just as the terror of rocket fire aimed at innocent Israelis is intolerable, so, too, is a future without hope for the Palestinians," he then added. "Our hearts go out to Palestinian civilians who are in need of immediate food, clean water, and basic medical care." To that end he called on Israel to open the border crossings and on the Palestinian Authority - helped with funds and support through an international donors conference - to a play a role along with the international community in monitoring the access points. "It will be the policy of my administration to actively and aggressively seek a lasting peace between Israel and the Palestinians, as well as between Israel and its Arab neighbors," he said. The subject of Israeli-Palestinian peace was the first foreign policy issue Obama addressed in his trip to the State Department, which came on the day Hillary Clinton assumed office following her Senate confirmation Wednesday. She also introduced a second envoy, Richard Holbrooke, who will serve as point man on Afghanistan and Pakistan. Obama was criticized even before taking office for remaining silent during the recent Gaza violence, and the Mitchell announcement - coupled with his remarks on the subject - seemed a bid to demonstrate that he is now fully engaged in the issue after relieving himself of the shackles of the transition period. "We have come to the State Department today to send a very clear message that we will reinvigorate American diplomacy," declared Vice President Joe Biden, who accompanied Obama on his first meeting with Clinton at her new headquarters. Mitchell, for his part, said the long-term conflict "demands our maximum effort no matter the difficulties, no matter the setbacks. The key is the mutual commitment of the parties and the active participation of the United States government." "Nowhere is a robust diplomatic approach needed more," Clinton said, referring to the Middle East, Afghanistan and Pakistan, stressing the role that diplomacy and development would play under her watch. Clinton also spoke to both Prime Minister Ehud Olmert and Palestinian Authority President Mahmoud Abbas by telephone. Olmert congratulated Clinton on her new position and told her Israel was interested in continuing to advance the Middle East peace process and intended to increase humanitarian aid efforts in Gaza. He also stressed Israel's commitment to preventing terrorism and arms smuggling into the Strip. Abbas told Clinton he would work with the new US administration for a comprehensive peace settlement in the Middle East. A statement from his office said Clinton and Obama would work to create a Palestinian state and to alleviate the suffering of Gaza's residents. Jordan's King Abdullah also congratulated Clinton on her new role, pressing the importance of launching serious and effective peace negotiations, according to the Jordanian Embassy. Israel's ambassador to the US, Sallai Meridor, welcomed the news of Mitchell's role, saying in a statement, "Israel holds Senator Mitchell in high regard and looks forward to working with him on taking the next steps towards realizing a future of peace and security for Israel and her neighbors." Earlier in the day, Obama signed orders to close the Guantanamo Bay detention center within a year and to ban the harshest interrogation methods. At the State Department, Obama said the United States "will not torture" as it detains terror suspects and works to keep the country safe. AP contributed to this report.