WASHINGTON (AP) — For the second straight week, average long-term U.S. mortgage rates inched up this week as financial markets awaited the Federal Reserve's crucial decision on interest rates.

Mortgage giant Freddie Mac said Thursday the average rate on a 30-year fixed-rate mortgage edged up to 3.91 percent from 3.90 percent a week earlier. The rate on 15-year fixed-rate mortgages rose to 3.11 percent from 3.10 percent.

Capping months of feverish speculation, Fed policymakers may finally raise a key interest rate on Thursday. A rate hike by the Fed could bring higher rates for home loans. The Fed has kept its key short-term rate at a record low near zero since the financial crisis struck seven years ago.

With the job market now considered essentially recovered from the Great Recession, many economists say it's time to start edging toward normal rates. Others argue that many other factors — notably a sharply slowing China, the tumult in markets and persistently less-than-optimal inflation — raise serious concerns. They say the Fed should wait, until later this year or even 2016.

To calculate average mortgage rates, Freddie Mac surveys lenders across the country at the beginning of each week. The average doesn't include extra fees, known as points, which most borrowers must pay to get the lowest rates. One point equals 1 percent of the loan amount.

The average fee for a 30-year mortgage was unchanged from last week at 0.6 point. The fee for a 15-year loan declined to 0.6 point from 0.7 point.

The average rate on five-year adjustable-rate mortgages rose to 2.92 percent from 2.91 percent; the fee held steady at 0.5 point. The average rate on one-year ARMs fell to 2.56 percent from 2.63 percent; the fee slipped to 0.2 point from 0.3 point.