U.S. foreclosure filings increased for the first time in three months by 9 percent in May, according to a Thursday report by listings site RealtyTrac.

Filings, which include default notices, auctions and bank repossession, rose from the previous month to 205,990 properties, or one in every 639 households. The value was down 4 percent from the prior year. Foreclosure starts increased in 33 of 50 states.

U.S. foreclosure activity has now decreased on a year-over-basis for 20 straight months including May, but the jump in May foreclosure starts shows that it's going to be a bumpy ride down to the bottom of this foreclosure cycle, said Brandon Moore, CEO of RealtyTrac.