Insurgents in Iraq have killed 14 US soldiers in just two days, the US military has announced.
Many Suleiman Beg casualties were driven long distances for treatment
Twelve died in four attacks in Baghdad, officials said, where a four-month-old military "surge" has now reached its peak with some 160,000 troops deployed.
The US has also said it killed dozens of insurgents on the first two days of a major operation north of Baghdad.
Elsewhere at least 15 people died and 40 others were hurt in a suicide truck bomb attack in northern Iraq.
The attack in Suleiman Beg, 90km (55 miles) south of Kirkuk, destroyed part of a local council office and several nearby homes.
The casualties included several women and children, hospital officials said.
Insurgents 'will respond'
The latest round of attacks on US forces raised the numbers of Americans killed in June to 59, the AFP news agency reported.
In the worst incident, five soldiers were killed by a roadside bomb in north-eastern Baghdad on Thursday. That attack also killed three Iraqi civilians and an Iraqi interpreter, the US said.
Four died in another bomb attack in the west of the city on Wednesday, with three others killed in two more strikes. Two more soldiers were killed by a bomb in the western province of Anbar.
Earlier, the commander of US forces in Iraq said he expected al-Qaeda in Iraq to respond to the military build-up around Baghdad with one of its own.
In an interview with a British newspaper, Gen David Petraeus said the truck bomb attack on an important Shia mosque in Baghdad that killed at least 78 people on Tuesday was an example of this.
"They wanted to make sure that the headlines about the launch of the offensive don't create too much hope," he told The Times.
Gen Petraeus also said up to 80 al-Qaeda volunteers were crossing into Iraq from Syria every month, all of them seen as potential suicide bombers.
Gen Petraeus also said he believed a group which kidnapped five Britons - a computer expert and his four bodyguards - in Baghdad last month had links to Iran.
He said the kidnappers were part of a secret cell of the Mehdi Army, a militia loyal to the radical Shia cleric, Moqtada Sadr.
"They are not rank-and-file Jaish al-Mehdi. They are trained in Iran, equipped with Iranian [weapons], and advised by Iran," he added.
Tehran has denied supporting militant groups in Iraq.
US offensive continues
Gen Petraeus's comments came after his forces conducted several different operations against al-Qaeda and other insurgent strongholds on the outskirts of Baghdad.
Operation Arrowhead Ripper began on Tuesday
The BBC's Andrew North in Baghdad says US commanders believe these "belt areas", as they call them, are where many of the car bombs set off in the capital are made.
Heavy fighting has been reported in Baquba, a city in Diyala Province, where US and Iraqi forces are conducting the largest offensive.
The US military says at least 41 insurgents have been killed in the first two days of Operation Arrowhead Ripper, but local officials say there have also been civilian deaths.
Operations have also been launched against Sunni militants south of Baghdad.
Troops reportedly destroyed 17 boats believed to have been used by insurgents along the River Tigris and detained at least 60 people.
There have also been intense clashes in the southern cities of Nasiriya and Diwaniya between coalition forces and Shia militias.