Israeli official says shift of troops is a step to exit

Israeli Foreign Minister Yitzhak Shamir told the US that Israel's redeployment of forces in Lebanon is the first step to withdrawal of all its forces from the war-torn nation. The Reagan administration has expressed concern that the pullback could leave Lebanon permanently divided. He said Israeli forces would complete the pullout ''as soon as possible.''

Mr. Shamir also said Israel, the US, and Lebanon were committed to the withdrawal of all outside forces from Lebanon. An American official said that included Syrian and Palestine Liberation Organization forces as well.

Meanwhile, Christians in southern Lebanon protested in large numbers, for the first time, against reported Israeli moves to close down Christian Phalangist Party offices and militia barracks.