US job openings increased sharply in September while layoffs fell, supporting economists' views that the labor market remained on firmer footing despite tepid employment gains during that month. Job openings, a measure of labor demand, had risen by 333,000 to 7.523 million by the last day of September, the Labor Department's Bureau of Labor Statistics said in its Job Openings and Labor Turnover Survey, or JOLTS report, on Tuesday. Data for August was revised slightly higher to show 7.190 million vacancies instead of the previously reported 7.079 million.