While political attention is riveted on Iowa, Democratic presidential candidate Wesley Clark (search) is closing the once-commanding lead that former Vermont Gov. Howard Dean (search) had in New Hampshire.

The tightening of the New Hampshire race has prompted Dean to revise his strategy and is injecting new energy into the retired Army general's campaign.

Clark is not competing in the kickoff Iowa caucuses on Jan. 19 and instead is focusing much of his energy and attention on New Hampshire's Jan. 27 primary.

Clark campaigned here Monday and Tuesday and was due back on Wednesday.

Locked in a close four-way fight in Iowa, Dean spent Tuesday in Vermont and planned a campaign stop in New Hampshire before heading back to Iowa.

Private polling by two campaigns in New Hampshire showed that Dean's lead has shrunk to single digits from a first-of-the-year high of about 25 percentage points, according to officials familiar with the polls.

However, an independent poll, by the American Research Group, Inc., showed Dean with 34 percent support and Clark with 20 percent in the three-day period that ended Monday, far ahead of the rest of the field.

Meanwhile, the Dean campaign, concerned that Clark is closing the gap in New Hampshire in a week in which the other major candidates are focusing on Iowa, plan to deploy surrogates and other campaign tactics to question Clark's shifting views on the war, ties to the Republican Party, commitment to abortion rights and special interest connections.

Mo Elleithee, a spokesman for Clark in New Hampshire, said the Dean campaign was getting nervous. "Clearly, they're hearing our footsteps, and they're resorting to the tired, old politics of attacks," he said.

The Dean camp also began running a new anti-war ad in Iowa.

"Where did the Washington Democrats stand on the war?" an announcer asks in Dean's ad, which drew protests from his rivals. "Dick Gephardt wrote the resolution to authorize war. John Kerry and John Edwards (search) both voted for the war."

Clark was spared criticism in the ad, but officials familiar with Dean's strategy said the retired Army general was about to become a campaign target. There were no plans to run ads criticizing Clark before Iowa's caucuses.

For his part, Clark sought anew on Tuesday to dismiss criticism from his rivals that he had vacillated on the war in Iraq, signaling earlier support for it.

"I've been opposed to this war from the start," Clark told reporters after a campaign stop at a child health clinic in Manchester.

"I watched with dismay as it emerged," he said. "It was a mistake."

He also called for a congressional investigation into the lead-up to the war "to bring all the relevant factors in and find out exactly why we did go into Iraq."

Dean aides expect he will face questions Wednesday in New Hampshire on Clark's rise. They said he may use the opportunity to point out differences between his record and Clark's.

The anti-war ad and sharpened rhetoric are part of a risky strategy for Dean, particularly in Iowa, where negative campaigning in the run-up to the caucuses is usually received poorly.

Dean campaign manager Joe Trippi said aides were attentive to Clark's rise, but not surprised by it since Clark bypassed Iowa to concentrate on New Hampshire.

"He's been shooting free throws by himself on one end of the court while we've been throwing elbows at each other at the other end," Trippi said.

With polls showing Dean running strong in key early states, he's come under increasing fire from his rivals. The attention has forced him to balance the need to respond to attacks against the fallout from doing so.

But Dean waded back into the fight Monday when he criticized his rivals by name and said he was tired of being treated like a "pincushion."

Sen. John Edwards, D-N.C., who has seen his own polling figures rise in Iowa, predicted that the race would get closer in New Hampshire, too. He blamed attack tactics of his opponents for helping to narrow the gap.

"I think it's ironic that I've now come under attack in Iowa," Edwards said in an interview in New Hampshire. "I've run a positive campaign."

Meanwhile, the Rev. Jesse Jackson said Tuesday that some of Dean's Democratic rivals have succumbed to "mad Dean disease." He warned that the party would self-destruct if the campaign remained "too hostile and too bloody."

As did Clark, Sen. Joseph Lieberman of Connecticut also chose to sit out the Iowa primary and to focus on New Hampshire.