The Soviet Union has increased its military presence in the Persian Gulf since the Iran-Iraq cease-fire despite publicly urging withdrawal of foreign navies from the region, a top U.S. commander said in Manama, Bahrain. “I see no withdrawal of the Soviets in this area,” said Gen. H. Norman Schwarzkopf, who commands U.S. forces in the gulf in his post as chief of the U.S. Central Command. “As a matter of fact . . . I see an increase in their diplomatic initiatives . . . and their military assistance initiatives.” Schwarzkopf said there has been a gradual reduction of U.S. forces in the gulf since the Aug. 20 cease-fire but that the United States will keep at least six warships in the region.