First-time filings for state unemployment benefits rose 1,000 to 323,000 last week, the Labor Department reported Thursday. The four-week average of initial claims increased by 500 to 330,500 in the week ending May 21, a five-week high. The four-week average smoothes out distortions caused by one-time events, such as weather, holidays and strikes. Economists were expecting a small increase in initial claims to about 326,000, according to a survey conducted by MarketWatch. Initial claims in the week ending May 14 were revised higher by 1,000 to 322,000. Meanwhile, the number of people receiving weekly benefit checks fell by 22,000 to 2.574 million in the week ending May 14. The four-week average of continuing claims rose by about 6,000 to 2.59 million. A Labor Department spokesman said there were no special seasonal factors that impacted the latest data.