Asian markets were mixed on Friday as dealers bought back cheap stocks after a week of heavy selling, although trading remained cautious amid fears of a debt default by the United States.
The dollar was pressured after another agency warned of a downgrade for Washington's credit rating, although it was supported by comments from the Fed chief that the bank was not ready for a new round of monetary easing.
Tokyo gained 0.39 percent, or 38.35 points, to 9,974.47 and Seoul added 0.71 percent, or 15.13 points, to 2,145.20 while Shanghai rose 0.35 percent, or 9.73 points, to 2,820.17.
Sydney closed 0.38 percent, or 17.2 points, lower at 4,473.5 and Hong Kong gave up 0.30 percent, or 64.82 points, to 21,875.38.
Global markets slumped this week as fears of a default in European economies were compounded by growing concern that politicians in Washington are unable to hammer out a budget that will allow a rise in the debt ceiling.
Economists and finance and business leaders have warned that failure to raise the ceiling above the current $14.3 trillion would send shockwaves through the world economy as it struggles out from the financial crisis.
Federal Reserve chairman Ben Bernanke reiterated warnings that a default would damage the US economy, telling the Senate Banking Committee it would be a disastrous "self-inflicted wound".
Adding to the troubles was Moody's decision on Wednesday to put the US's gold-standard triple-A debt rating on credit watch with the possibility of a downgrade. That was followed on Thursday by a similar move by another agency, Standard & Poor's.
Christopher Gore, currency analyst at Go Markets, told Dow Jones Newswires: "The lack of closure to the US debt ceiling (problem) continues to weigh on market sentiment.
"US politicians are seemingly playing a game of chicken with the debt ceiling for the purpose of political gain while the ratings agencies stand at the ready to clip the US debt rating."
The greenback was given some support after Bernanke told Congress that the Fed was not ready for a new round of quantitative easing, which has the effect of reducing the dollar's value by increasing the money supply.
On Wednesday, he had indicated that further easing was possible if economic weakness persisted, fuelling a stock market rally as investors hoped for a new round of stimulus from the Fed.
The dollar was trading at 79.22 yen in Europe, up slightly from 79.13 yen late Thursday in New York. However, it is up from the high-78 range in Asia earlier Thursday.
The euro eased to $1.4135 from $1.4141. The European single currency inched up to 112.02 yen from 111.87 yen.
In Sydney mining giant BHP Billiton fell 1.63 percent after it announced it was buying US firm Petrohawk Energy in a deal with a total value of $15.1 billion.
And Rupert Murdoch's News Corp fell 2.83 percent after the FBI began a probe over potential phone hacking in the United States following a scandal in Britain that saw the closure of Sunday tabloid the News of the World.
Oil was mixed. New York's main contract, West Texas Intermediate light sweet crude for delivery in August, gained 19 cents to $95.88 per barrel in the afternoon.
Brent North Sea crude for September shed 40 cents to $115.86 on its first trading day.
Gold closed at $1,578.00-$1,579.00 in Hong Kong, up from Thursday's close of $1,582.50-$1,583.50. It opened at $1,585.00-$1,586.00.
The precious metal, a safe-haven in times of economic uncertainty, surged to a record $1,594.45 per ounce in New York Thursday.