Europe's debt crisis is translating into lower mortgage rates for Americans as investors fleeing to the refuge of U.S. bonds push borrowing costs close to December's record low.

The average U.S. rate for a 30-year fixed mortgage fell to 4.78% in the week ended Thursday, from 4.84%, Freddie Mac said. The record low is 4.71%.

Concerns about rising government deficits and debt in Greece, Portugal and Spain have devalued the euro and sent equity markets tumbling globally. Investors seeking the safety of U.S. bonds, including mortgage-backed securities, are driving down home loan rates, said David Berson, the chief economist at PMI Group Inc. in Walnut Creek, Calif.

"The more concern there is about Europe, the lower interest rates will go," Berson said.

The 30-year rate may fall to a record in coming weeks, he said.

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