A Turkish opposition leader called Tuesday for a mass rally to protest bombings that killed 17 people in a mostly residential neighborhood of Istanbul. Deniz Baykal's appeal reflects national outrage over Sunday's twin bombings, which Turkish officials blamed on Kurdish rebels. The guerrillas deny responsibility. Turkish Prime Minister Recep Tayyip Erdogan also told Turks on Tuesday they should unite in the face of terrorism. His Islamic-oriented government is locked in a dispute with Baykal and his allies, who accuse the government of trying to undermine secular principles in Turkey's constitution.