HOLLAND, Michigan — An angry President Barack Obama vented at Washington's poisoned politics Thursday, hitting back after a wave of criticism during one of his worst weeks in the White House.

On a trip to the heartland, Obama argued that the United States should never have lost its AAA credit rating, stripped away by Standard & Poor's last week, blaming Republicans in Congress for the embarrassment.

"This downgrade you have been reading about could have been entirely avoided if there had been a willingness to compromise in Congress," Obama said, lashing out in a fiery speech in a Michigan electric battery factory.

"The only thing keeping us back is our politics," he said, complaining that some of his foes in Congress were putting party ahead of country.

"There are some in Congress right now who would rather see their opponents lose than America win. That has to stop. We are supposed to all be on the same team, especially when we are going through tough times."

"There is nothing wrong with our country. There is something wrong with our politics. There's something wrong with our politics that we need to fix."

In the speech, which had all the characteristics of a campaign pitch for Obama's 2012 election bid, the president called on Congress to endorse an extension of a payroll tax cut and to pass long-stalled free trade pacts.

"Do you want to put people to work right now rebuilding America?... you have got to send that message to Congress," Obama roared, in an unusually aggressive speech.

Obama was to attend two lucrative fund-raisers in New York City, as he returns to filling his campaign coffers following a month-long showdown with Republicans over debt which pushed his reelection bid into the background.

Obama is being assailed by foes in the Republican Party and elements of his own Democratic base over turmoil in the economy, especially unemployment, which remains at 9.1 percent amid a stagnant recovery.

The Michigan factory, Johnson Controls, received $300 million from the president's economic stimulus plan -- which was pilloried by Republicans -- and has created 150 jobs in Michigan and Wisconsin.

The White House said its efforts will ensure that the United States produces 40 percent of the world's advanced batteries by 2015.

Republicans frequently ridicule Obama's expenditures on green energy jobs and manufacturing, arguing that the government should get out of the way of private business and allow the market to dictate where jobs are created.

Obama will try to reconnect with US voters on a bus tour of Minnesota, Iowa and Illinois next week, amid rising criticism of his leadership as fears mount of a return to recession.