The top U.S. military commander in Iraq says a failure to curb militant bombings and other attacks there could lead to foreign investors pulling out.
General Lloyd Austin said that "security improvements" in the south that had spurred economic development were threatened by "externally supported illegal militias and other extremists."
He spoke after 28 people were killed and dozens wounded in a twin bombing outside a government building north of Baghdad.
A car bomb and a roadside bomb blew up in a crowded parking lot outside a government office in Taji, some 20 kilometers north of the Iraqi capital, Baghdad.
The attack comes amid a recent spike in insurgent attacks.
At least 10 police and soldiers were killed in a string of attacks over the country over the past three days.
Three women and two children were killed in a rocket attack near the Rashid Hotel in central Baghdad late on July 4.
Analysts say Iraq has seen a rise in attacks as U.S. forces prepare to withdraw by December.
Fifteen U.S. soldiers were killed in June, the deadliest month in three years for U.S. forces in Iraq.
It was also the worst month for civilian deaths since January with 155 killed.
Against that backdrop, Prime Minister Nuri al-Maliki has urged Iraqi lawmakers to consider whether to allow some U.S. combat troops to stay beyond their year-end departure deadline.
According to AP, the White House is offering to keep up to 10,000 combat troops in Iraq next year.
The Senate's top Democrat, Harry Reid, however, told AP he opposed any U.S. troop extension in Iraq, given the costs and the U.S. debt crisis.
Reid estimated nearly $1 trillion has been spent in Iraq since the U.S. invasion in 2003, with $50 billion spent there this year alone.
compiled from agency reports