U. S. Accuses Soviet Of Plot to Blackmail State Dept. Official
US Amb to Moscow Malcolm Toon sends protest note to USSR claiming that Soviet secret police agent tried to blackmail Amer diplomat into working for Soviet intelligence; incident, which occurred on Oct 16 in Soviet Georgia, involved Constantine Warvariv, Paris-based deputy US delegate to UNESCO who was in Russia for conf; Warvariv claims Soviet KGB agent threatened to expose him as Nazi collaborator in World War II; says agent left when he denied their accusation and refused to cooperate with him; US Embassy publicizes incident after Soviet press agency Novosti distributes article about Warvariv's supposed association with Nazis (M)