Senior Palestinian officials said militant groups in the Gaza Strip agreed to stop firing missiles at Israel at midnight Saturday, if Israel launches no new raids into Gaza. But two main guerrilla groups denied that any agreement had been reached. The Palestinian officials said the unilateral cease-fire was aimed at ending an Israeli offensive in the Gaza Strip that began June 28, three days after militants raided an Israeli army post, killing two soldiers and capturing 19-year-old Cpl. Gilad Shalit. Full Story