The number of Americans filing new claims for unemployment insurance fell 20,000 last week, the government said on Thursday, more than Wall Street economists had expected. First-time claims for state jobless aid fell to 321,000 in the week ended May 14 from an upwardly revised 341,000 the previous week, the Labor Department said. "A 20,000 move is slightly more than random noise," said Keith Hembre, chief economist for U.S. Bancorp Asset Management in Minneapolis. A Labor Department analyst said there were no special factors behind the drop. The closely watched four-week moving average, which irons out weekly volatility, climbed for the second straight week, rising 5,500 to 329,750. The number of people remaining on benefit rolls after drawing a week of aid rose for the third consecutive week, advancing 5,000 to 2.60 million in the week ended May 7, the latest week for which figures are available.