Mortgage rates ran a tepid streak started three weeks ago by hovering at around 4 percent this week, according to Freddie Mac, largely because investors continue to flee European sovereign bonds for the safe haven of U.S. Treasury debt.

Mortgage giant Freddie Mac and finance Web site Bankrate.com released weekly surveys that tracked mortgage rates.

For Freddie, rates for the benchmark 30-year fixed-rate mortgage inched forward by a percentage point, placing it at 4 percent after the loan averaged 3.99 percent. Bankrate.com noted the same difference, reporting that the 30-year loan fell to 4.24 percent this week, down from 4.25 percent last week.

The finance Web site saw the 15-year fixed-rate mortgage slide from 3.50 percent last week to 3.47 percent this week, while Freddie observed a 3.31-percent average, up from 3.30 percent.

“This was another week of pretty tame movement in mortgage rates,” Greg McBride, a senior financial analyst

with Bankrate.com, tells MReport. “The key driver of rates remains the European debt crisis, which is helping to keep mortgage rates near record lows.”

The European debt crisis continues to rattle markets. Backing off of a popular referendum for an unpopular bailout package with austerity measures, Greek Prime Minister George Papandreou stepped down recently, with mainland technocrat Lucas Papademos replacing the ousted leader.

Italian Prime Minister Silvio Berlusconi added to the brouhaha over possibilities for sovereign default in Europe – a scenario that would devastate financial and capital markets, if disorderly – by also recently resigning his position.

Less confidence in European sovereign bonds continues to drive investors to Treasury debt, widening Treasury yields and keeping a heel on mortgage rates at a time when a double-dip recession still seems possible for the global economy.

Frank Nothaft, Freddie’s VP and chief economist, highlighted low mortgage rates in a statement while citing “potential for further gains in the near term” for the economy.

He also cited rising retail sales, consumer confidence, and homebuilder confidence as reasons to believe that the economy may soon see a boost.

The 5-year Treasury-indexed adjustable-rate mortgage (ARM) also fell by one percentage point for Freddie, which recorded 2.97 percent for the loan, down from 2.98 percent last week. The 1-year ARM went up from 2.95 percent to 2.98 percent.

Bankrate.com meanwhile saw 3.17 percent for the 5- and 1-year ARMs, just one point above 3.16 percent last week.