A top aide allegedly told Saddam Hussein in a phone conversation in the 1980s that he intended to "change the social reality" in a Shiite town where the former Iraqi leader came under an attack, according to a tape played Monday by prosecutors in Saddam's trial.

Taha Yassin Ramadan — a co-defendant in the trial — allegedly said "suspicious elements" in Dujail would be moved out and "replacements" brought in. In the tape, a voice said to be Saddam's replied, "Fine."

Prosecutors played the tape in court Monday in the trial of Saddam and seven of his former regime members over a crackdown launched in Dujail after the former Iraqi leader's motorcade was shot at in July 1982. Hundreds were arrested in the sweep, some allegedly tortured, and 148 were killed.

One defendant, Barzan Ibrahim, denounced the tape as a fake, and the defense stepped up its attempts to cast doubt on a series of documents prosecutors have presented to show Saddam and his co-defendants' role in the sweep against Dujail.

Top defense lawyer Khalil al-Dulaimi demanded prosecutors give more detail on how the documents — including memos from Saddam's office and Ibrahim's Mukhabarat intelligence agency — were obtained and repeated his call for international handwriting experts to check signatures.

A team of Iraqi experts have authenticated Saddam's and other signatures on the documents in the past two sessions.

But on Monday, a report by the team read to the court questioned signatures purported to be those of one defendant, Mizhar Abdullah Ruwayyid.

The prosecution had said Ruwayyid, a Baath party official in Dujail, sent a letter to the Interior Ministry informing on Dujail families days after the ambush of Saddam's motorcade.

But the experts said the handwriting on the letter did not match samples given by Ruwayyid. The report did not elaborate, but Ruwayyid has insisted the letter is a forgery, as have other defendants about their own signatures, since authenticated by the experts.

After the report was read, however, defense lawyers did not pick up on the failed match in their arguments against the documents.

After a 90-minute session, chief judge Raouf Abdel-Rahman adjourned the trial until May 15. The defense is expected to start presenting its case soon, and on Monday presented the judge with eight pages of witnesses it intends to call to the stand.

The audiotape was a surprise piece of evidence that prosecutors said they obtained only a day before — without saying where. They said it was a 1986 phone conversation between Saddam and Ramadan, a member of the Revolutionary Command Council, a top leadership body.

The speaker said to be Ramadan did not elaborate on the intention to change Dujail's social fabric — and it's not clear to what extent such a plan was carried out.

In other cases, Saddam's regime was known to encourage Sunni loyalists to move to areas with Shiite or Kurdish populations. But hundreds of Dujail Shiite families who were arrested in the 1982 sweep were released from prison years later and allowed to return to the town, which remains overwhelmingly Shiite.

With the tape, prosecutors appeared to be aiming to show Saddam was closely involved in the crackdown in Dujail — and that his regime's actions went far beyond a simple search for the perpetrators of the attack on the former Iraqi leader.

In the tape, the alleged voice of Ramadan said the leveling of farms and palm groves in the town of Dujail, carried out as retaliation for the attack, had been nearly completed and that the owners would be given compensation.

He said the razing around Dujail and the nearby Shiite town of Balad was an opportunity "to create a new city and prevent violations ... to reorganize the two cities (Dujail and Balad) to be modern."

"We will move out the suspicious elements and bring in replacements, meaning we will an attempt an operation of changing society, we will greatly change the social reality," he said.

The speaker said to be Saddam responds, "Fine, good night," ending the tape, which lasted a few minutes.

Ibrahim, Saddam's half brother and former intelligence chief disputed the tape and the documents.

"Where are you getting these documents? Whose hands are behind them?" Ibrahim said.

"Forging documents and imitating signatures is an age-old phenomenon," he said. "There have big strides in forging documents and CDs. ... I can bring anyone with any knowledge of a computer and do the same thing in front of you."

The defense has insisted that the regime's actions were a legal response to the assassination attempt — including the sentencing to death of 148 Shiites. The prosecution argues the men were sentenced in a show trial in which they could make no defense.

"We didn't kill them. The court sentenced them to death. There is a huge difference between killing and transferring the defendants to the court," Ibrahim said. "They carried out an operation, an attempt on the president's life."

"We are not killers and you know that," he said. "We are patriotic Iraqis who serve our people and country."