Ex-general called to lead Uruguay to new elections

The Council of State proclaimed retired Gen. Gregorio Alvarez President for a 3 1/2-year term beginning Sept. 1 and directed him to prepare Uruguay for its first elections since 1971. The unanimous action by the council ratified a decision made by the ruling junta, which has speeded plans for a return to democratic rule by lifting the ban on political activities and easing up on press censorship.

General Alvarez, the mastermind of a military takeover in 1973, will succeed President Aparicio Mendez, a conservative who served since 1976. Mr. Alvarez is to prepare the nation for elections b efore his term ends March 1, 1985.