At least 67 people have been killed and almost 100 have been wounded in two separate bombings in Baghdad, Iraqi police have said.
In one attack, a fuel tanker exploded near a petrol station in the mainly Sunni suburb of Mansour, killing 50.
Earlier, at least 17 people were killed and 32 injured in a blast in the mainly Shia shopping district of Karrada.
Elsewhere, US officials said three of its troops had been killed, and the UK said a British soldier had died.
The Karrada bomb was placed in a parked vehicle and went off in an area with many electronics stores and a popular ice-cream parlour, reports say.
A car bomb in the same area killed 25 people last week.
Karrada has been hit by a string of bombs in the past 10 days. On Monday of last week, four separate car bombs killed 16 people.
US and Iraqi forces have tightened security in Baghdad since earlier in the year in an attempt to stem such bombings.
In other developments, the main Sunni Arab political bloc in Iraq, the Iraqi Accordance Front, has said it is withdrawing from the government.
The group, which has six cabinet ministers, said the Shia-led administration had failed to meet a list of demands, including one urging tough action against Shia militias.
The Sunni leaders had also demanded a bigger say in security matters.
And Iraqi officials say more than 1,600 civilians were killed in July - an increase of about a third from the previous month.
The figure is also higher than the number of civilian deaths in February, when the US launched its so-called surge, which involved sending thousands more troops to Baghdad.
The US military says American casualties fell last month to their lowest level this year.
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