(Bloomberg News) Federal Reserve Chairman Ben S. Bernanke said U.S. Treasury securities remain a "safe haven" for investors after Standard & Poor's lowered its credit rating on the nation's debt in August.

"The downgrade didn't scare off any investors," and the action, along with the prospect of other downgrades, hasn't done "significant damage" to the economy, Bernanke said today in response to a question at a town-hall-style event in El Paso, Texas. At the same time, the nation must take measures to establish a sustainable path for the national debt amid rising Social Security and health-care costs, he said.

Partisan disagreement this year over raising the U.S. debt ceiling prompted the Standard & Poor's rating cut without provoking signs of concern in financial markets that the country will default. Treasuries returned 6.4 percent in the third quarter, the most since the final three months of 2008, compared with a 14 percent drop in the benchmark S&P 500 Index.

Whenever financial market volatility increases because of concern about issues such as the European debt crisis, "people come in and buy Treasuries, because they view that as really among the very safest and most liquid investments in the world," Bernanke said to soldiers at the military's Fort Bliss.

Ten-year Treasuries fell today, with yields rising 9 basis points, or 0.09 percent, to 2.08 percent at 1:48 p.m. in New York. The S&P 500 rose 1 percent to 1,241.79.

Bernanke said earlier in today's event that the central bank is concentrating "intently" on reducing unemployment and projects inflation to stay under control for the "foreseeable future."

"For a lot of people, I know, it doesn't feel like the recession ever ended," even with the economy growing for two years, Bernanke said.

The event is part of Bernanke's effort to explain to Americans his rationale for the central bank's unprecedented bailouts of financial firms and efforts to spur economic growth. Bernanke and his colleagues are struggling to reduce unemployment stuck near 9 percent or higher for more than two years after lowering interest rates almost to zero and using unconventional tools to ease credit.

Joblessness is "painfully high," with more than two- fifths of unemployed people out of work for longer than six months, "by far the highest ratio since World War II," Bernanke said in comments before taking questions for almost an hour. "These problems are very serious, and we at the Federal Reserve have been focusing intently on supporting job creation."