The United States' failure to pass a financial rescue package would be an "economic catastrophe'', Barack Obama's spokesman said today.

The Illinois senator, and his Republican rival John McCain, both urged the US Congress to act as the financial crisis engulfing the US continued to dominate the race to the White House with issues such as Iraq, foreign policy, education and health care all being overshadowed.

Obama campaign spokesman Bill Burton said the failure of the lower house of Congress to pass the $700 billion US dollar rescue package yesterday showed why US voters were ``disgusted'' with the leadership in Washington.

Bringing change to Washington has been a key aspect of the Democrat's campaign this year.

``Every American should be outraged that an era of greed and irresponsibility on Wall Street and Washington has led us to this point, but now that we are here, the stability of our entire economy depends on us taking immediate action to ease this crisis,'' Mr Burton said.

Earlier, Mr Obama said Congress should not start from the beginning as US political leaders considered their next move in the wake of the House's rejection of what he called ``the economic rescue plan''.

``Given the progress we have made, I believe we are unlikely to succeed if we start from scratch or reopen negotiations about the core elements of the agreement,'' the 47-year-old Illinois senator said.

``But in order to pass this plan, we must do more.''

His campaign also released a two-minute TV advert which claimed his rival would offer four more years of the same unpopular policies of the Bush administration.

``I know that we can steer ourselves out of this crisis,'' Mr Obama says. ``But not by driving down the very same path.''

The Republican National Committee also released its own advert which claimed the Mr Obama's economic plan ``will make the problem worse''.

Mr McCain tied himself to the crisis last week when he suspended his campaign and said he would not take part in last Friday's presidential debate unless a deal was agreed, before changing his mind at the last minute.

Today, the 72-year-old Arizona senator told reporters in Des Moines: ``Our leaders failed to act.''

Earlier, he told CNN's American Morning: ``We haven't convinced people that this is a rescue effort, not just for Wall Street but for Main Street America, for working families, for small businesses, the heartland of America - all over America.

``We didn't do a good enough job.''

Yesterday, Mr McCain accused Mr Obama and his Democratic allies in Congress of infusing the process with ``unnecessary partisanship''.

``Now is not time to fix the blame, it's time to fix the problem,'' he said.

Both candidates talked to President George Bush about the crisis today and both avoided calling the plan a bail-out.