“We will not allow the Iraqi people’s democratic transition to be hijacked by those who might wish to install another form of dictatorship,” Rumsfeld added in his warning. “There is no question that the government of Iran has encouraged people to go into the country and that they have people in the country attempting to influence the country,” Rumsfeld said.

The second-in-command of the main Iranian-based Shiite opposition group told followers in Baghdad yesterday that Shiites would not accept a government imposed by US forces. “We will not take part in any government that is imposed on us,” Abdul Aziz Al-Hakim told a gathering of several hundred followers.

US forces netted a former top Iraqi spy hours after capturing Tareq Aziz, Saddam Hussein’s best-known apologist. A US official said Farouk Hijazi was detained near Iraq’s border with Syria.

He was director of external operations for Iraq’s intelligence agency in the mid-1990s, when it allegedly attempted to assassinate former President George Bush, father of the current US leader, during a visit to Kuwait.

Talking of Hijazi, Rumsfeld said: “He is significant. We think he could be interesting but I would rather not give any details.”

The urbane, silver-haired Aziz, former deputy prime minister and number 43 on a US list of 55 most-wanted Iraqis, gave himself up in Baghdad on Thursday night.

“He did surrender. He is currently being questioned by coalition forces,” a US military spokesman said in Qatar.

“It’s very possible he may know the status of Saddam and other regime officials, potentially the location of other regime officials, and where they may be hiding,” said a Pentagon official, who asked not to be identified.

At Baghdad’s Abu Hanifah Nouman Mosque, Sunni Sheikh Moayyad Ibrahim Al-Aadhami told worshipers during Friday prayers: “Let’s say no to America, no to the occupation. We won’t replace one tyrant with another.”

In Riyadh, Arab League Secretary-General Amr Moussa held talks on Iraq and the Palestinian question with Crown Prince Abdullah, deputy premier and commander of the National Guard. The two men “discussed the current Arab situation as a whole, in particular the situation in Iraq and the Palestinian cause” and examined “means for developing the mechanisms for joint Arab action” on the issues, the Saudi Press Agency said.

The United States meanwhile blocked international efforts to allow a United Nations Human Rights Commission investigator of crimes under Saddam Hussein to look at the post-Saddam period.

Although the commission asked the investigator to produce a report in the next few months, it agreed — under what diplomats said was strong US pressure — that this should focus on what had happened during the long rule of the ousted president.