WASHINGTON, March 13 (UPI) -- Interest rates for both 30-year and 15-year fixed-rate mortgages in the United States increased this week, Freddie Mac (NYSE:FRE) reported Thursday.

At 6.13 percent, the average 30-year fixed interest rate gained over last week's average of 6.03 percent with mortgages including an average of 0.5 points. The 30-year fixed-rate mortgage averaged 6.14 percent a year ago, the report said.

Fifteen-year fixed rate mortgages also increased, averaging 5.6 percent with an average of 0.5 points. A week ago 15-year fixed rate mortgages averaged 5.47 percent, while a year ago they averaged 5.88 percent, the weekly report said.

"Average mortgage rates were up for all loan products," said Freddie Mac chief economist Frank Northaft. "However, for the first 11 weeks so far this year, the average 30-year fixed rate is still below 5.9 percent, and the average 30-year rate in January was the lowest since July 2005."

"The combination of lower house prices and lower mortgage rates contributed to a more affordable market for home buyers," Northaft said.