BAGHDAD, Iraq \ufffd The U.S. military did not count people killed by bombs, mortars, rockets or other mass attacks \ufffd including suicide bombings \ufffd when it reported a dramatic drop in the number of murders around Baghdad last month, the U.S. command said Monday.

The decision to include only victims of drive-by shootings and those killed by torture and execution, usually at the hands of death squads, allowed U.S. officials to argue that a security crackdown that began in the capital on Aug. 7 had more than halved the city\ufffds murder rate.

But the types of slayings, including suicide bombings, that the U.S. excluded from the category of \ufffdmurder\ufffd were not made explicit at the time. That led to considerable confusion after Iraqi Health Ministry figures showed that 1,536 people had died violently around Baghdad in August, nearly the same number as in July.

The figures raise serious questions about the success of the security operation launched by the U.S.-led coalition. When they released the murder rate figures, U.S. officials and their Iraqi counterparts were eager to show progress in restoring security in Baghdad, at a time when the country looks to be on the verge of civil war.

At the end of August, the top U.S. military spokesman in Iraq, Maj. Gen. William B. Caldwell, said violence had dropped significantly because of the operation. Caldwell said \ufffdattacks in Baghdad were well below the monthly average for July. Since Aug. 7, the murder rate in Baghdad dropped 52 percent from the daily rate for July.\ufffd

Caldwell, however, did not make the key distiction that the rate he was referring to excluded a significant part of the relentless daily violence that tears through Baghdad. On Monday for example, at least 20 of the 26 people who died in the capital were killed in bombings.