South Korean President Moon Jae-in on Friday called for stern clampdowns on churches violating quarantine rules, as officials race against the clock to control a recent spike in coronavirus infections caused by a church cluster.The country reported 324 new cases on Friday, the eighth straight day of triple-digit increases and the first time the number crossed the 300-mark since March 8, bringing its total caseload to 16,670.South Korea’s ‘grave situation’ after biggest virus surge in five…