The average 30-year fixed interest rate averaged 6.08 percent with an average 0.6 point during the week, compared with 5.98 percent for the previous week, Freddie Mac (NYSE:FRE) said.

A year ago, 30-year fixed rate mortgages averaged 6.42 percent.

At 5.66 percent with an average 0.6 point, the 15-year fixed rate average gained over the previous week's average of 5.55 percent.

A year ago, 15-year fixed rate mortgages averaged 6.12 percent.

"Mortgage rates drifted up this week over market concerns that the Federal Reserve Board may raise short-term rates later this year," Freddie Mac chief economist Frank Nothaft said.

"While existing house prices continue to decline, new home sales unexpectedly rose in April and the number of month's supply of new homes for sale fell from 11.1 months in March to 10.6 months in April," he said. " Moreover, the median sales price for new homes rose 1.5 percent in April from the same month in 2007, representing the first yearly increase since November 2007."