Knesset Speaker Reuven Rivlin said Thursday that Israel will fight against deteriorating security conditions in Sinai. "Israel will not allow half of the Sinai Peninsula to fall back to terrorism and war," he said at a ceremony in memory of the fallen soldiers of the 1954 Suez Crisis in Jerusalem.Rivlin said that Israel's longstanding peace with Egypt is still being tested. "These days we hear that Israel's peace with Egypt is contingent upon Israeli-Palestinian negotiations. Such statements are unacceptable." He added that "the peace agreement between Israel and Egypt is clearly in the mutual interest both countries."