Baghdad, Iraq ? The number of American military deaths in Iraq reached 1,000 Tuesday as Defense Secretary Donald Rumsfeld cast the death toll as evidence that the United States was aggressively engaging terrorists around the world.

The grim milestone comes amid a heated presidential campaign in which the decision to go to war in Iraq has become one of the central and most divisive issues.

“Taking the offense (against terrorism) … of course has its cost, just as staying on defense has its cost,” Rumsfeld said at a Pentagon news briefing before the White House announced that the toll had reached 1,000.

He added: “If you think about the fact that we have thousands of patrols every day. … If you take all of those patrols, and look at the number of incidents, they’re relatively small.”

Rumsfeld took the unusual step Tuesday of saying that U.S. and coalition forces “probably” had killed between 1,500 and 2,500 former regime elements, criminals and terrorists last month. Pentagon officials generally have not been revealing enemy body counts, only occasionally offering estimates of enemy dead in specific incidents.

Rumsfeld’s decision Tuesday to provide an estimate for a full month was interpreted by some military analysts as a Bush administration effort to try to offset bad news from Iraq.

“They’re grasping for good news,” said Michael E. O’Hanlon, an expert on military affairs with the Brookings Institution. “They’re in the situation where they needed something positive to say.”

Bush did not directly comment on the tally, but both he and Vice President Dick Cheney have vigorously defended the war in recent days. Sen. John F. Kerry, the Democratic presidential nominee, has repeatedly branded it the wrong war at the wrong time and place.

On Tuesday, Kerry focused on the gravity of the loss to thousands of loved ones. Kerry called the 1,000th U.S. military death in Iraq “a tragic milestone” during a campaign stop in Erlanger, Ky.

“I think that the first thing that every American wants to say today is how deeply we each feel the loss, how much this means to all of us as Americans, the sacrifice that we feel on a very personal level,” he said. “And our thoughts and our prayers are with the families that most recently have learned of a loss of a loved one, but also with all of those others who are still working through their pain.”

A July CBS News/New York Times poll found that the rising death toll was resonating among voters. Asked if the result of the war in Iraq was worth the cost in American lives, 62 percent of respondents said it was not worth it, while 34 percent said it was. The poll had a margin of error of 3 percentage points.