WASHINGTON -- Rates on 30-year mortgages rose this week to the highest level in 15 months.

In addition, Freddie Mac said one-year adjustable rate mortgages were at the highest level in four and a half years.

The mortgage giant said the national average for 30-year, fixed-rate mortgages stands at 6.10 percent.

That was the highest level since 30-year mortgages were at 6.21 percent in July 2004.

It was up from 6.03 percent last week.

A competing survey from Bankrate.com showed that the average 30-year, fixed-rate mortgage increased from 6.1 percent to 6.17 percent.

Freddie Mac said rates on 15-year, fixed-rate mortgages, a popular choice for refinancings, averaged 5.65 percent this week. That was up from 5.62 percent last week.

One-year adjustable rate mortgages rose to 4.89 percent. That was up from 4.85 percent last week.

The one-year ARM was at its highest level since April 2002.

Analysts said the rising mortgage rates reflect growing nervousness in financial markets about inflation pressures triggered by the sharp rise in energy prices after the Gulf Coast hurricanes shut down production.