Sales of new U.S. single family homes fell for the first time in three months in May, but inventories of new homes for sale reached record lows and the median sales price rose slightly, a government report showed on Thursday.

The Commerce Department said May new home sales fell 2.1 percent to a seasonally adjusted annual rate of 319,000. Analysts polled by Reuters were expecting a slightly slower pace of 310,000 for the month.

The decline ended two straight months of strong gains, with sales rising 6.5 percent in April and 8.9 percent in March. May's new home sales were 13.5 percent above the May 2010 level.

Signaling a paring back of builder inventories in the deeply depressed U.S. housing market, the supply of new homes for sale fell to a record low of 166,000 from 172,000 in April. Houses completed and houses under construction in the month also fell to their lowest levels on record.

The Commerce Department report showed that the median new home sales price rose to $222,600 in May from $217,000 in April, marking the first increase since December last year. However, compared to a year earlier, the May median sales price was down 3.4 percent

At May's sales pace, the supply of homes on the market dropped to 6.2 months' worth, the lowest since April 2010.