JACKSONVILLE, Fla. | John McCain still believes the fundamentals of the nation's economy are strong even as the uncertain fate of two of Wall Street's oldest institutions sent stocks tumbling.

In remarks to a crowd of several thousand in this pivotal electoral state, the Arizona senator said he agreed there should be no taxpayer-financed bailout of Lehman Brothers even as the investment banking giant filed for bankruptcy. Meanwhile, Merrill Lynch was selling itself to Bank of America for less than half of the iconic brokerage firm's recent value.

Reacting to the turmoil on Wall Street, the Dow dropped some 300 points.

"Our economy, I believe, still, the fundamentals of our economy are strong, but these are very, very difficult times, so I promise you: We will never put America in this position again. We will clean up Wall Street," McCain said.

He added: "The McCain-Palin administration will replace an outdated, patchwork quilt of regulatory oversight and bring transparency and accountability to Wall Street. We will have transparency and accountability and we will reform the regulatory bodies of government."

The GOP nominee underscored his message with a new campaign television commercial that seemed to contradict his rosier assessment of the country's economic health.

By The Associated Press