BAGHDAD, Iraq — Two former Iraqi commanders denied gassing Kurdish civilians in northern Iraq 20 years ago, telling Saddam Hussein’s genocide trial Thursday that they used only conventional weapons against Kurdish rebels and Iranian troops.

Sultan al-Tai, minister of defense under Saddam, and Gen. Hussein Mohammed, a deputy director of army operations, testified to rebut evidence presented by prosecutors in videos and documents this week.

The documents, prosecutors said, showed Saddam’s government sanctioned the use of “special weapons” — mustard or nerve agent — against Kurdish civilians as well as rebel fighters in 1987-88.

In sometimes emotional testimony, al-Tai alleged some of the documents implicating him in waging chemical warfare were forged. “I didn’t use any special weapon against the Kurds,” al-Tai shouted at the judges.

The two men, Saddam and four other former members of his regime have pleaded innocent to charges of war crimes and crimes against humanity for their roles in the military campaign, code-named Operation Anfal. The campaign took place during the 1980-88 Iraq-Iran war.

An estimated 180,000 Kurds died during the operation. Saddam and one other defendant have pleaded innocent to the additional charge of genocide.

Al-Tai and Mohammed argued Thursday — shouting at times — that Iranian forces had infiltrated northern Iraq and were using Kurdish rebel bases to attack government troops.

Both men insisted they used only conventional weapons and both said they were carrying out their superiors’ orders.

“My job allowed me only limited responsibility,” Mohammed told the court. “In an army, a deputy commander is not the responsible person.”

He challenged evidence presented by prosecutors. “Did I sign these documents?” he demanded. “Is my name on them? If it’s there, I’ll sign my execution myself.”

The chief judge, Mohammed Oreibi al-Khalifa, interrupted to say: “Prosecution documents show that special weapons were used, but you say they weren’t from army warehouses?”

“No,” Mohammed responded.

“So they didn’t belong to you,” the judge asked.

“Of course not,” Mohammed said.

“So, where did they come from?” al-Khalifa asked.

“I don’t know. Had I known, I would’ve told you. You have to ask other people — the military industrialization department,” Mohammed replied, provoking a smirk from Saddam, sitting in the dock alongside him.

Al-Tai said the government relocated Kurdish civilians for their safety during the campaign.

“We removed all civilians from the fighting zones. The civilians were transferred in trucks … and they were put in safe houses,” al-Tai said.

Chief prosecutor Munqith al-Faroon scoffed at this claim.

“I wonder where the people in the mass graves come from?” al-Faroon asked the judges rhetorically. “How were they transferred to the mass graves? Maybe in the same trucks that went to the safe houses he’s talking about!”

“We saw documents. We watched videos incriminating them. What more do we need — believe the documents and the videos or believe him?” the prosecutor said.

The trial was adjourned to Jan. 8.

At an earlier trial, Saddam was condemned to death for the killing of nearly 150 people in the town of Dujail after a 1982 attempt to assassinate him. His lawyers have appealed both the verdict and sentence, and the appeals court is expected to rule next month.

Iraqi officials suggest that Saddam’s prosecution on genocide charges would be halted if the appeal court upholds the death sentence of the first trial.

Al-Bashir reported from Baghdad and Halaby from Amman, Jordan. Some material in the story came from a pool report of the Baghdad trial.