The number of people filing initial applications for U.S. state unemployment benefits unexpectedly increased to the highest level in four months last week, but the underlying trend continued to point to a strengthening labor market, the government reported Thursday. The Labor Department said jobless claims rose by 19,000 to 316,000 last week, in contrast to economist expectations that claims would fall. The four-week moving average of claims—considered a better measure of labor-market trends because it smoothes weekly volatility—rose 6,750 to 298,000 last week. The measure has remained below 300,000—a level associated with a strengthening labor market—for 18 consecutive weeks. U.S. employers have added at least 200,000 jobs in each of the last 11 months, the longest such period since 1994. Almost 3 million new jobs were created in 2014, the strongest annual increase since 1999.