Radical Shia Cleric Withdraws Backing for Iraq Security Drive

America's security surge in Baghdad was dealt a double blow yesterday when the radical Shia cleric Moqtada al-Sadr abruptly withdrew support for the crackdown, and a female suicide bomber killed at least 40 people at a Baghdad college.

There were concerns meanwhile about the health of the Iraqi president, Jalal Talabani, who was flown to Jordan for medical tests after falling ill. Officials denied he had had a heart attack, saying he was exhausted and low blood pressure had briefly left him unconscious.

The flurry of developments amounted to another bad day for the authorities in Baghdad, who had claimed that the capital was being brought under control as a result of the new joint US-Iraq security plan. The prime minister, Nouri al-Maliki, said on Saturday he was optimistic about the new security arrangements.

But yesterday a female bomber detonated the explosives in her vest after pushing her way past guards in the reception area of a largely Shia college that is part of Mustansiriya University. A 22-year-old student, Muhanid Nasir, said he saw a commotion at the gate. "Then there was an explosion. I did not feel anything for 15 minutes; when I returned to consciousness, I found myself in hospital." He suffered wounds to his head and chest.

Mr Sadr, who until now had supported the US-led security plan, last night said it was not working. "There is no benefit in this plan because it is controlled by the occupiers," an aide to the cleric said in a statement. American forces were "watching car bombs explode, taking the souls of thousands of innocent Iraqi people".

A volley of other bombings and rocket attacks also peppered Baghdad yesterday, belying claims of improved security. There was also concern that violence was radiating outwards from the capital. Senior Iraqi and US officers confirmed to the Guardian that Sunni fighters fleeing the operations in Baghdad were relocating in the area of the provincial capital, Baquba, 30 miles north of Baghdad. The city straddles supply lines for both Sunni and Shia fighters into Sadr City and Sunni areas of Baghdad. The rise in violence is forcing the US to deploy extra troops around Baquba.

Diyala province has become so volatile that the Pentagon has indicated that it may delay plans to turn over control of the area to the Iraqi military by the end of the year. Direct attacks on US soldiers are up by 70% in Diyala since last summer and fierce battles have raged since the Baghdad security plan was launched.