Iraq's largest Sunni Arab political bloc announced its withdrawal from the government Wednesday, threatening Prime Minister Nouri al-Maliki's efforts to seek reconciliation among the country's rival factions.
Meanwhile, at least 70 people were killed and 100 wounded in two explosions in Baghdad.
At least 50 were killed and 60 wounded when a fuel tanker exploded near a gas station in western Baghdad. Two police officers, both speaking to The Associated Press on condition of anonymity, said the explosion was the work of a suicide attacker.
In a separate attack, 17 civilians were killed in a car bombing.
The parked car bomb left a gaping crater in a busy square in central Baghdad. Three minibuses and six cars were damaged by flames and flying debris. Karradah was previously thought to be one of central Baghdad's safest areas.
The blast occurred around 2 p.m. in Mansour, a primarily Sunni neighborhood on the western side of the Iraqi capital.
The withdrawal from government of the Sunni bloc Accordance Front, which has 44 of the parliament's 275 seats, is the second such action by a faction of al-Maliki's "national unity" coalition in its 14-month tenure.
Five Cabinet ministers loyal to radical Shiite cleric Muqtada al-Sadr quit the government in April to protest al-Maliki's reluctance to announce a timetable for the withdrawal of U.S. forces from Iraq.
Rafaa al-Issawi, a leading member of the Front, said at a news conference in the capital that the bloc's six Cabinet ministers would submit their resignations later in the day.
Al-Issawi said the decision to pull out from the government followed what he called al-Maliki's failure to respond to a set of demands put forward by the Front last week, when it gave the prime minister seven days to meet its demands. The ultimatum expired Wednesday.
Among the demands: a pardon for security detainees not charged with specific crimes, the disbanding of militias and the participation of all groups represented in the government in dealing with security issues.
"The government is continuing with its arrogance, refusing to change its stand and has slammed shut the door to any meaningful reforms necessary for saving Iraq," al-Issawi said.
"We had hoped that the government would respond to these demands or at least acknowledge the failure of its policies, which led Iraq to a level of misery it had not seen in modern history. But its stand did not surprise us at all," he said, reading from a prepared statement.
Also Wednesday, the U.S. military announced the deaths of three more soldiers, killed by a sophisticated, armor-piercing bomb in eastern Baghdad.
An explosively formed penetrator, or EFP, detonated near the soldiers' patrol during combat operations Tuesday, the military said. Six other soldiers were wounded.
That brought to 76 the July toll of U.S. deaths in Iraq. It was the lowest monthly count in eight months, as the U.S. military said it was gaining control of former militant strongholds.
Even so, it was the deadliest July for U.S. troops since the war began. For the previous three years, the month of July saw a relatively low death toll. In July 2006, 43 U.S. troops were killed in Iraq, and 54 died in each of the previous two Julys.
By contrast, July was the second-deadliest month for Iraqis so far this year, according to an Associated Press tally.
From NPR reports and The Associated Press