WASHINGTON - U.S. officials who say there has been a dramatic drop in sectarian violence in Iraq since President Bush began sending more American troops into Baghdad aren't counting one of the main killers of Iraqi civilians.

Car bombs and other explosive devices have killed thousands of Iraqis in the past three years, but the administration doesn't include them in the casualty counts it has been citing as evidence that the surge of additional U.S. forces is beginning to defuse tensions between Shiite and Sunni Muslims.

President Bush explained why in a television interview Tuesday. "If the standard of success is no car bombings or suicide bombings, we have just handed those who commit suicide bombings a huge victory," he told TV interviewer Charlie Rose.

Others, however, say that not counting bombing victims skews the evidence of how well the Baghdad security plan is protecting the civilian population -- one of the surge's main goals.

"Since the administration keeps saying that failure is not an option, they are redefining success in a way that suits them," said James Denselow, an Iraq specialist at London-based Chatham House, a foreign policy think tank.

Bush administration officials have pointed to a dramatic decline in one category of deaths -- the bodies dumped daily in Baghdad streets, which officials call sectarian murders -- as evidence that the security plan is working. Bush said this week that that number had declined by 50 percent, a number confirmed by statistics compiled by McClatchy Newspapers.

But the number of people killed in explosive attacks is rising, the same statistics show -- up from 323 in March, the first full month of the security plan, to 365 through April 24.

Overall, statistics indicate that the number of violent deaths has declined significantly since December, when 1,391 people died in Baghdad, either executed and found dead on the street or killed by bomb blasts. That number was 796 in March and 691 through April 24.

Nearly all of that decline, however, can be attributed to a drop in executions, most of which were blamed on Shiite Muslim militias aligned with the government of Prime Minister Nouri al-Maliki. Much of the decline occurred before the security plan began on Feb. 15, and since then radical Shiite cleric Muqtada al-Sadr has ordered his Mahdi Army militia to stand down.

According to the statistics, which McClatchy reporters in Baghdad compile daily from Iraqi police reports, 1,030 bodies were found in December. In January, that number declined 32 percent, to 699. It declined to 596 February and again to 473 in March.

Deaths from car bombings and improvised explosive devices, however, increased from 361 in December to a peak of 520 in February before dropping to 323 in March.

In that same period, the number of bombings has increased, as well. In December, there were 65 explosive attacks. That number was unchanged in January, but it rose to 72 in February, 74 in March and 81 through April 24.

U.S. officials have said that they don't expect the security plan to stop bombings.

"I don't think you're ever going to get rid of all the car bombs," Gen. David Petraeus, the top U.S. commander in Iraq, said this week. "Iraq is going to have to learn as did, say, Northern Ireland, to live with some degree of sensational attacks."

But some think that approach could backfire, with Iraqis eventually blaming the Americans for failing to stop bombings.

"To win, the insurgents just have to prove they are not losing," said Denselow, of London's Chatham House.

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