Click here to watch "Punch."

The on-air back-and-forth between Barack Obama and John McCain intensified Friday, as the Illinois senator continued to pound his opponent over a past business deal that led to job losses in Ohio and the McCain team shot back with another derisive ad about Obama's celebrity status.

Obama had already released a radio ad (subscription) in Ohio on Aug. 8 highlighting McCain's connection to DHL, the foreign-owned shipping company, which recently eliminated 8,200 jobs in the state.

On Friday, he followed up with "Punch" (subscription), a TV ad that features comments from Ohio residents distressed over the job losses. "If DHL -- I mean, if something happens, it's going to be like a ghost town," one woman frets. An announcer charges: "In Washington, John McCain helped pave the way for foreign-owned DHL to take over an American shipping company," eventually leading to the job cuts. He notes that McCain's campaign manager, Rick Davis, was a "lead lobbyist" for the company. "It's tough times when it's a foreign entity coming in and sucker-punching us," says an Ohio man who lost his job.

The McCain campaign was quick to respond, launching its own TV spot Friday afternoon. "Maybe" (subscription) cites a FactCheck.org analysis that calls Obama's allegations "misleading." "Maybe the applause is going to his head," an announcer remarks, as the same familiar footage of Obama in front of cheering crowds in Berlin plays on screen. He insists that "it's Obama’s taxes that will hurt Ohio families." And hitting once again upon the "inexperienced" argument, he concludes: "That's the real Obama: ready to tax, not ready to lead."

With its 20 electoral votes, Ohio is viewed as a crucial swing state for both candidates, and recent polling shows Obama and McCain in a dead heat.