NEW YORK (CNN/Money) - Mortgage rates posted their first increase in five weeks as homeownership rates hit a new record in the second quarter, mortgage financier Freddie Mac said Thursday in its latest report.

"Mortgage rates rose a little this week in response to expectations that the Federal Reserve Board is willing to move more aggressively if inflation should become an issue," Frank Nothaft, Freddie Mac vice president and chief economist, said in a press statement.

"So far, inflation seems to be under control, but if the economy should heat up too rapidly, the Fed would have to act quickly and decisively."

The rate on 30-year fixed-rate mortgages averaged 6.08 percent in the week ending July 29, with an average 0.6 point payable up front, up from 5.98 percent the previous week, Freddie Mac said.

A year earlier, the rate on the 30-year fixed-rate loan averaged 5.94 percent.

The 15-year mortgage rate rose to 5.49 percent from 5.39 percent, also with 0.6 point payable up front. Last year, rates stood at 5.27 percent.

One-year adjustable rate mortgages (ARMs) averaged 4.17 percent, up from 4.12 percent the week prior, with 0.6 of a point payable up front. At this time last year, the average rate for ARMs was 3.67 percent.

"In other news, the national homeownership rate reached an all time high, according to the Census Bureau, of 69.2 percent," Nothaft added. "This is but one indicator of how strong the housing market has been over the last number of years."

Freddie Mac's (FRE: down $0.47 to $64.11, Research, Estimates) average mortgage rates are based on a survey of 125 lenders nationwide.