Sen. John McCain speaks to supporters during a rally, in Cedar Rapids, Iowa, 18 Sep 2008

U.S. presidential candidate John McCain, a Republican, has attributed the current U.S. economic strife to systematic corruption, and says he would fire the government official in charge of regulating financial markets.

At a rally in the midwestern state of Iowa Thursday, Senator McCain said the Securities and Exchange Commission kept rules in place that allowed investors to turn U.S. markets into "casinos."  He pledged he would fire the chairman of the commission Christopher Cox, saying he betrayed the public's trust.  

Democratic nominee Barack Obama has accused McCain of long-supporting economic policies that discourage effective regulation.  In Nevada Wednesday, Senator Obama said the economic developments this week represent the final verdict on McCain's policies.

McCain and his vice presidential running mate, Governor Sarah Palin, Thursday criticized Obama's running mate, Senator Joe Biden, for suggesting that paying higher taxes is patriotic.

When Biden made the remark on ABC television's Good Morning America, he was referring to Obama's plan to raise taxes for anyone making more than $250,000 a year.

McCain also is campaigning in Wisconsin Thursday, while Obama is holding a rally in New Mexico.

A new opinion survey shows Obama has regained his lead over McCain.

A poll conducted jointly by The New York Times and CBS News shows Obama with a five-point lead over McCain (48 percent to 43 percent) among registered voters.  

Some information for this report was provided by AP and Reuters.