Israel's blockade of the Gaza Strip is an "atrocity," former US president Jimmy Carter said after meeting with Hamas officials in Cairo. Carter also said he had asked Hamas officials to stop rocket attacks into Israel and defended his controversial meetings with the Palestinian terrorist group, saying it was necessary to talk to all parties to achieve peace. Carter met Thursday for the second straight day with Hamas officials, holding talks with some of the group's leaders from the Gaza Strip in the Egyptian capital. He is expected Friday in Syria - the latest stop on a tour he calls a private Middle East peace mission - where he said he will meet with Hamas's exiled political chief Khaled Mashaal, as well as Syrian President Bashar Assad. The meetings with Hamas, which Washington considers a terror organization, have drawn sharp criticism from Israeli and US officials. But Carter strongly defended the need to reach out to Hamas, which won Palestinian parliament elections in 2006. "You can't have an agreement that must involve certain parties, unless you talk to those parties to conclude the agreement," Carter said in a speech Thursday at the American University in Cairo. "You have to involve Hamas ... They have to be involved in some way." He said that although "there is very strict restraint or prohibition" against any US or Israel official speaking with Hamas "I know there are some officials in the Israeli government who are quite willing to meet with Hamas and maybe that will happen in the near future." Carter said he had requested from the Hamas leaders that they stop rocket attacks into Israel from Gaza, which have prompted IDF military assaults on the Strip. Any "killings of civilians is an act of terrorism," he said. He said that during his visit to Israel, the first stop on his regional tour, he saw rockets that had been fired by Hamas and "met with people who lost loved ones." "At the same time, if you live in Gaza, you know that for every Israeli killed in any kind of combat, between 30 to 40 Palestinians are killed because of the extreme military capability of Israel," Carter said, describing the Israel-imposed siege of Gaza as an "atrocity." Carter lamented that "very little progress has been made" in the 30 years since he brokered Israel's historic peace agreement with Egypt, bringing him the Nobel Peace Prize. "Israelis are suffering as well as Palestinians and they both need peace," he said. Before Carter's appearance at the university, a Hamas delegation with about 15 members was seen heading into the hours-long meeting at a Cairo hotel with Carter. The meeting was closed to the media and held under heavy security shortly after Carter and Egyptian President Hosni Mubarak met. The Hamas delegation in Cairo, headed by Gaza leaders Mahmoud Zahar and Said Siyam, was not available for comments later Thursday. Zahar, in commentary published in The Washington Post Thursday, said Carter's talks with Hamas were "sensible" and would bring "honesty and pragmatism to the Middle East while underscoring the fact that American policy has reached its dead end." Hamas officials have touted the meetings as a recognition of their legitimacy after their 2006 election victory. After that win, Hamas formed a Palestinian government that was shunned by the West and Israel and relations between Hamas and Palestinian Authority President Mahmoud Abbas deteriorated. In his editorial, Zahar said no peace plan can succeed "unless we are sitting at the negotiating table and without any preconditions." But he said negotiations were not possible until Israel withdraws from the West Bank and dismantles settlements, then talks could be begin on the return of Palestinian refugees. There was more criticism of Carter in Washington, where US Congressman Joe Knollenberg, a Republican from Michigan, proposed legislation to prohibit federal funding of the Atlanta, Georgia-based Carter Center. The bill has very little chance of approval. Democratic presidential hopeful Sen. Barack Obama also criticized Carter, saying he had a "fundamental disagreement" with the former president. "We must not negotiate with a terrorist group intent on Israel's destruction," Obama said. In Israel, all the country's senior political leaders except President Shimon Peres declined to meet with Carter when he visited. After his planned trip to Syria, Carter is also to visit Saudi Arabia and Jordan before returning to Israel late Sunday.