CHICAGO (Reuters) - U.S. Democratic presidential candidate Barack Obama attacked Republican rival John McCain as a tool of big oil companies in a television ad released on Monday.

Seeking to tap into Americans’ anger over soaring gasoline prices, Obama’s ad opens with a shot of a driver pumping gas and refers to huge profits made by oil companies in the past year.

“Every time you fill your tank, the oil companies fill their pockets,” a narrator says. “Now Big Oil’s filling John McCain’s campaign with $2 million in contributions.”

The ad shows McCain standing next to fellow Republican President George W. Bush as the narrator says, “After one president in the pocket of big oil -- we can’t afford another.”

The ad touts Obama’s plan to offer American families $1,000 tax breaks to help offset higher energy costs as well as the Illinois senator’s proposal for a tax on windfall oil company profits. It accuses McCain, an Arizona senator, of seeking to give oil companies additional tax breaks.

The McCain campaign said the ad was misleading and failed to mention that the Republican candidate voted against a 2005 bill that provided billions in tax breaks for energy producers, including oil companies aimed at offering incentives for domestic energy production.

Obama voted for the bill, which was backed by Bush.

“Barack Obama’s latest negative attack ad shows his celebrity is matched only by his hypocrisy,” McCain spokesman Tucker Bounds said in a statement.

“Also not mentioned is the $400,000 from big oil contributors that Barack Obama has already pocketed in this election,” Bounds said.

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With U.S. voters anxious about $4 a gallon gasoline amid economic weakness and a deteriorating job market, Obama plans to focus on the topic of energy. He is to travel to Lansing, Michigan, on Monday and will make stops in Ohio and Indiana on Tuesday and Wednesday.

Obama’s proposal for a windfall oil profits tax has drawn criticism from those who say it proved to be counterproductive when it was last put in place in the United States in 1980 during the final year of President Jimmy Carter’s administration.

Those critics say the measure prompted oil companies to cut back on domestic production while failing to raise as much in tax revenue as lawmakers expected. It was repealed in 1988 during the Reagan administration.

Obama’s aggressive new ad is the latest salvo in an intensifying battle on the airwaves. In ads that have drawn controversy, McCain has sought to cast Obama as an arrogant “celebrity” candidate who lacks the substance to lead.

An ad titled “Celeb” features shots of socialite-actress Paris Hilton and singer Britney Spears as well as shots of Obama speaking at a huge campaign event to try to imply that he is more of a celebrity icon than a potential chief executive.

But the ad was criticized by Hilton’s mother, Kathy Hilton, who has contributed to McCain’s campaign and called the advertisement a “waste of money.”