U.S. fixed mortgage rates this week remained at or near all-time lows, serving as an incentive for refinancing and purchasing, said the Primary Mortgage Market Survey released Thursday by Freddie Mac.

The mortgage giant said that 30-year fixed-rate mortgage (FRM) was 3.88 percent for the week ending March 8, down from last week' s 3.90 percent. Last year at this time, the 30-year FRM averaged 4. 88 percent.

The 15-year FRM dropped to a new record low of 3.13 percent. A year ago at this time, the 15-year FRM averaged 4.15 percent.

The 5-year Treasury-indexed hybrid adjustable-rate mortgage ( ARM) averaged 2.81 percent, down from last week when it averaged 2. 83 percent. But the 1-year Treasury-indexed ARM rose slightly to 2. 73 percent.

The average rates don't include extra fees, known as points, which added the rates up by 0.6 percent to 0.8 percent.

Rates on the 30-year loan have been below 4 percent for three months, which made home-buying and refinancing more attractive for those who can qualify.

The Obama administration Tuesday announced a new mortgage relief plan to help responsible homeowners by reducing half of the refinancing fee charged by the U.S. Federal Housing Administration.

Recently, the U.S. housing market has seen modest improvement. However, many economists hold that the U.S. housing market still needs years to recover entirely.