BAGHDAD — The U.S. military has noted a "significant improvement" in the aim of attackers firing rockets and mortars into the heavily fortified Green Zone in the past three months that it has linked to training in Iran, a top commander said today.

Lt. Gen. Ray Odierno, the top day-to-day U.S. commander in Iraq, also expressed cautious optimism over a decline in the number of American troops killed this month. At least 60 U.S. troops have died so far in July after the death toll topped 100 for the previous three months, according to an Associated Press tally based on military statements.

Odierno said it appeared that casualties had increased as fresh U.S. forces expanded operations into militant strongholds as part of the five-month-old security operation aimed at clamping off violence in the capital, but were going down as the Americans gained control of the areas.

"We've started to see a slow but gradual reduction in casualties and it continues in July," he said at a joint news conference with Iraqi military commander Maj. Gen. Abboud Qanbar. "It's an initial positive sign, but I would argue we need a bit more time to make an assessment whether it's a true trend."

Iraqis in Baghdad swept up debris from bloodstained pavement, a day after two suicide bombings killed at least 50 cheering, dancing, flag-waving Iraqis celebrating the national soccer team's semifinal victory in the Asian Cup tournament.

The attacks bore the hallmarks of Sunni militants who have fueled the violence tearing at the fragile fabric of Iraq for nearly four years. But these bombings, in parked cars less than an hour apart in separate corners of Baghdad, appeared designed to gain attention rather than target a particular sect.

An ice cream parlor was the backdrop for the first attack on Wednesday, charring the interior of the corner store in the predominantly Sunni Mansour neighborhood in west Baghdad. At least 30 people were killed and 75 wounded, according to the Interior Ministry.