US airplanes Sunday mistakenly bombed a convoy of Kurdish forces working with US Special Forces. The attack killed 18 Kurds and wounded 45 others, including the brother of Massoud Barzani, the president of the Kurdistan Democratic Party, which controls this autonomous area of northern Iraq. Mr. Barzani's son was also injured in the attack.
It was not clear at press time whether there were casualties among US Special Forces, who assisted in the operation.
Just outside Dibagah, Kurdish pesh merga forces Sunday had been trading firewith retreating Iraqi positions when they sent messages for backup in the form of US air bombardments, says Adburrahman Kawrini, a commander and trainer of a division of pesh mergas, whose Kurdish name means "those who face death."
The US airplanes, he said, hit the wrong crossroads - one where the pesh mergas, trailed by a reporting crew from the BBC, were surveying Iraqi positions.
The incident could put a strain on relations between the US and its Kurdish allies at a moment when cooperation is crucial for coordinating an offensive against the Iraqi-controlled cities of Kirkuk and Mosul.
KDP leaders, allied with the US in the war against the Iraqi regime, were quick to characterize the incident as an unfortunate, tragic accident.
"We know it was not intentional. Many parts of the northern front have become more active than before. This type of incident, though regrettable, we have seen many of them during this campaign," said Hoshyar Zebari, the KDP's leading official on external affairs.
"We hope this will be the last one. This does not and will not undermine our resolve, our commitment to continue very closely with the US, with the coalition in order to achieve our common goals, which is regime change and liberation of the people of Iraq."
But the incident was a worrying development nonetheless, showing the fallibility of a tactic that has become the main dynamic in the days since the northern front against Saddam Hussein's regime has gradually opened.
The pesh merga forces battle on the ground with Iraqi forces and then coordinate with the US to provide information about where to deliver aerial bombardments.
The strategy is proving effective, says Mr. Zebari, because it was keeping half of Saddam Hussein's forces occupied and wearing them down.
"These forces are pinned down. These forces are harassed. These forces are attacked," he said. "The strategy is to push them and to push them as much as can be done."
In the wake of the bombing, Kurds struggled to clean up the resulting carnage, which included at least 10 military vehicles that were a mangled, blackened and still smoking mess Sunday afternoon shortly after the incident.
A burned-out blue jeep marked "TV" - a falsely protective shield all members of the media have taken to taping in bold letters onto their cars - was being lifted and towed away. The vehicle belonged to the BBC, three of four members of whom were injured. An intepreter working for the group was among the 18 killed.
Wajeeh Barzani, the KDP president's brother who was seriously injured in the attack, is a key commander involved in organizing the pesh merga to cooperate in operations with the US Special Forces.
His unit had called for air support for attacks on Iraqi forces that were 200 to 300 meters from the pesh merga. After he was critically injured in the mistaken attack, his condition stabilized and he was flown to Germany for medical treatment.
One of his comrades was tracking the retreating Iraqis when the bombs were dropped, sending him flying to the ground.
"All of a sudden, a plane appeared and then they bombed, and pieces of God-knows-what were flying up all over the place," said Abdurrahman Kawrini, who had bloodied cuts on his face, arms, and legs from the attack.
"I saw an ocean of fire and people screaming," he added.
As journalists surveyed the acrid, burning scene, the Iraqi military in nearby Kirkuk and Mosul continued to lob shells into the empty hillsides close to the area where the incident took place.
Mr. Kawrini, still slightly dazed, said he lost track of how many of his footsoldiers he had lost. He said he did not think there was any intentional attack on the convoy.
"This is a mistake. They don't want to kill us on purpose. We are allied with the Americans," he said.
After the incidents, thousands of soldiers and civilians lined the road leading toward Dibagah. They watched with long faces as carloads of reporters and pesh merga soldierscame out to survey the damage.
Outside the Emergency Surgical Center for War Victims, as many as 3,000 people lingered unhappily, waiting for more news of what had happened to some of their most elite fighters.
Watching from a hilltop hazy from both overcast weather and the burning smoke from the wreckage, many pesh mergas vowed to continue to work with their American allies, and said they understood that the bombing, however awful, was unintentional.
"I am sad, not angry. I'm still ready to fight alongside the American troops to defeat the Iraqi regime," says Zerar Mohammed Taher, a mid-level commander. "It was a mistake."