BAGHDAD – Explosions killed at least 20 people and wounded as many as 100 Saturday night at a downtown market in Iraq’s second-largest city, a senior official said, coming at the end of a violent day that also saw the slaying of seven policemen around the country.

It was the latest spate of attacks to come as all but 50,000 U.S. military troops head home by the end of the month.

Deputy provincial council chairman Sheik Ahmed al-Sulayti said he was alerted by police late Saturday about the rising death toll in Basra, located 340 miles southeast of Baghdad.

Al-Sulayti said at least 20 were killed by the blasts that came within minutes of each other at central Basra’s al-Ashaar market. He said an estimated 100 were injured.

But as is common in the immediate chaos after Iraq explosions, the death toll varied among officials. A senior commander in Basra’s security operations center said 43 people were killed and more than 200 wounded. Another report had as many as 60 people dead.

Officials also differed over the cause of the blasts. Two police officials said a roadside bomb and a car packed with explosives caused the explosions. But Basra Police Chief Adil Daham said the explosions were caused by a malfunctioning power generator.

Television footage showed bloodied bodies being loaded into ambulances amid hysterical bystanders, some of whom blamed Iraq’s stalled government for the bloodshed.

“Why do they not agree, while the victims are falling down?” shouted one unidentified man. “The politicians are after posts and chairs. Reach an agreement, you traitors.”

Five months after parliamentary elections that failed to produce a clear winner, Iraq’s leaders have yet to form a new government. In Basra, where power outages have stymied air conditioning units in the searing summer temperatures, citizens have held demonstrations to blame politicians for the lack of public services.

In the most dramatic of the attacks Saturday on Iraqi security troops, gunmen killed five policemen in an overnight shootout that lasted until dawn at a suspected bomb workshop in western Baghdad, security officials said.