It was the latest in a series of attacks that initially focused on American and British forces in Iraq and that appear to be escalating to include Iraqi security forces cooperating with occupation forces.

The blast followed by one day the release of an audio message that claimed to be from Saddam Hussein, calling on Iraqis to resist the occupation by the Americans and the British and to punish any Iraqis who cooperate with them. Iraqis on Friday had warned reporters that they had heard that a large attack was being planned for this weekend.

Military officials also confirmed tonight that a freelance British journalist who had previously worked for the British television network ITN had been killed in Baghdad. A spokesman said that the body had been turned over to soldiers and that no details were available about his death. Other reports said the journalist had been shot while in a crowd outside the Iraq Museum. 

Earlier, American troops in northern Iraq faced protests from Turkish officials over what Turkey said was the detention by the Americans of 11 of its soldiers.

In Ramadi, more than 70 people were injured as shrapnel from the metal pole and the bomb ripped through a large crowd around noon, said the director of a hospital where the injured were treated.

On the street outside the police station, a shredded blue shirt and a pair of navy slacks from a recruit's new uniform lay near the spot where the dead and injured fell as the graduation ceremony ended. The event was meant to mark the successful transition from the old era of police torture and corruption to a new era of officers who are being trained to act as civil servants.

Lying in a hospital bed, Saadi Farhan, 17, a police recruit, said: "There was a great explosion. We don't know from where." Another wounded recruit, Ahmad Hammad, told a Reuters reporter, "We were marching in a file as part of our training when a roadside bomb exploded." 

Hospital and police officials said there were 7 dead and 74 wounded. No American officials were injured.

In Baghdad, the top American administrator in Iraq, L. Paul Bremer III, said that despite the increasing wave of violence directed at American and British forces in Iraq, "We will not let the Iraqi people down" by leaving. Mr. Bremer also said that though he wished that Saddam Hussein were in custody or dead, "every evidence" suggested that he was not in charge of the well-orchestrated resistance and that the Iraqis attacking allied forces "are a small group of desperate men — they do not pose a strategic threat to the Iraqi people or to the coalition."

Still, there was a sense of urgency in the planning today to turn over more power to a governing council of about 25 Iraqis. A number of Iraqis, as well as American experts on Iraq, have counseled the Bush administration to help bring Iraqi leaders to the fore even if it is considered too early for elections.

Mr. Bremer declined to name the candidates for the governing council. But several leading political figures said that he was negotiating with the Kurdish leaders Massoud Barzani and Jalal Talabani, along with a number of other political figures.

A meeting of Iraqi political figures was set for Monday in Erbil, where final decisions were likely to be made on whether to take part in the council, whose powers would be subordinate to those of the occupation authorities.

In Ramadi, on the street near the still-standing torn metal pole, residents gathered this afternoon and accused the American forces of planting the explosives. Iraqis who work with occupation troops as translators, policemen or contractors have increasingly become the objects of anti-American sentiment and intimidation.

Ramadi, about 60 miles west of Baghdad, is a bastion of Sunni Muslims, the minority that dominated during the Hussein era. Resistance to the occupation runs deep here.

The victims of the blast today filled two floors of Ramadi Hospital. Their new uniforms were torn, baring their wounds. Dr. Qussai al-Arawi, the hospital's director, said the wounds ranged from fractures to serious head injuries and that 52 people needed surgery. Three hours after the explosion, men sloshed rivulets of watery blood out of the hospital lobby with mops.

Reporters who came to photograph or speak with the injured did not get very far. Angry relatives interrupted interviews, and a shouting man who said he had five brothers hurt in the blast chased journalists toward the exit, saying, "I will plant a bomb on myself and blow up the whole hospital!" if they returned.

The cadets, who a police lieutenant, Yassir Abdul Hamid, said ranged in age from 17 to 28, had gone through a three-day course with senior Iraqi police officers and members of a National Guard unit who are American police officers.

In the past two days, guard patrols have come under attack from rocket-propelled grenades, and mortar shells have landed in the yard of their compound.

The classes were in a secondary school near the central police station. Today, the first 250 cadets graduated, only to be surprised by the blast as they left the ceremony. 

"No good citizen could do this horrible thing," said Lieutenant Hamid. "So I think it was a terrorist act by someone who wanted to destabilize the system." But several witnesses said that the Americans had put several checkpoints on the street, called Doctors Street, last night, and that they had left the school early today. They offered these observations as proof that the Americans were responsible for the explosion.

"Every day they were with us, practicing with us — why didn't they come today," Mr. Farhan said.

Luai Nori, 20, who owns a copy shop across the street, said of the Americans, "If it were up to me I would rip them apart."