Palestinian Authority Chairman Mahmoud Abbas on Sunday called on Israel "to take constructive steps" in response to a new Arab peace initiative. The Arab League last week relaunched a dormant 2002 Saudi plan offering peace with Israel in exchange for a full withdrawal from lands captured in the 1967 Mideast War. Prime Minister Ehud Olmert has hailed the plan as a "revolutionary change" but expressed reservations as well. "I call on the Israeli government to take constructive steps to answer the peace initiative put forward by Arab countries," Abbas said at a news conference with visiting German Chancellor Angela Merkel, who is the current EU president. Standing next to Abbas, Merkel welcomed the Arab initiative, but said it was not a final plan. "It's clear when you negotiate, that you have to talk to each other, and often the opening position is not the final position, but that you have to find a compromise. Many Arab countries now show a sense of responsibility. I feel there is good will on both sides. What is necessary is to build trust," she said, before calling for Palestinians to release kidnapped soldier Gilad Schalit. Abbas also reiterated his calls for the soldier's release, but he has been unable to persuade Hamas-allied militants to free the young man. Merkel called on both Israel and the Palestinians to seize the "window of opportunity" opened by the new international peace push to end their conflict. "I believe time is of the essence. We have to try to reach results as quickly as possible," she said. She also said she spoke with Abbas about the demands by the Quartet of international mediators that the new coalition government between Fatah and Hamas recognize Israel, renounce violence and accept past peace agreements. With the Palestinian government refusing to meet those conditions, international sanctions that prevent millions of dollars from flowing through the Palestinian Cabinet have remained in place. "My request is to do everything possible to ensure that the entire national unity government will accept the Quartet's criteria. Only those who renounce violence, accept Israel's right to exist and accept previous agreements, can be a partner in further (peace) efforts," she said. Earlier today Merkel spoke about Europe's help in bringing Israel and the Palestinians back to the negotiating table, trying to build on a new burst of international efforts to restart peace talks. Merkel, who met with Foreign Minister Tzipi Livni early Sunday morning, said the Europeans are ready to offer support, but ultimately the sides must resolve their differences themselves. "The Europeans must not assume that they could force a solution. We can't and I don't want to do it," she said in her speech. "Within my abilities, I would like to support the sides to walk the path toward peace." Sunday's stops included breakfast with Livni and a tour of Yad Vashem. Merkel spent about half an hour at the Holocaust museum, visiting the Hall of Remembrance and laying a wreath decorated with ribbons bearing the German flag. Before leaving, she wrote in the memorial's guest book: "Humanity grows out of responsibility for the past." Later, Merkel went to the Hebrew University of Jerusalem, where the former physics researcher received an honorary doctorate. Merkel called on Iran to immediately release 15 British sailors and marines seized in the Gulf on March 23. "Britain has the full solidarity of the European Union," Merkel said in a speech at the university. "We demand the immediate release of the 15 British soldiers." "We admire your steadfast friendship with the Jewish people," Hebrew University President Menachem Magidor said. In the evening, Merkel will meet with Prime Minister Ehud Olmert in Jerusalem.