Soviet officials and Afghan resistance leaders have begun unprecedented talks in Saudi Arabia on gaining freedom for Soviet soldiers held by the guerrillas. Western dip-lomats in the Saudi capital of Riyadh said two rounds of talks were held Sunday and more meetings were expected Monday. Moscow says the negotiations are aimed at gaining freedom for Soviet soldiers captured by mujahideen guerrillas. The talks mark the first time Soviet President Mikhail Gorbachev has sanctioned direct negotiations at such a senior level with rebel leaders since Moscow's intervention in Afghanistan in 1979.