BAGHDAD, Iraq (CNN) -- - The Baath Party, the political movement that ruled Iraq during the Saddam Hussein era, is warning there will be "grave consequences" if former Iraqi leader Saddam Hussein is executed.

Saying it would hold the United States responsible, a message appeared on al-basrah.net Tuesday that read: "The Baath and the resistance are determined to retaliate in all ways and all places that hurt America and its interests if it commits this crime."

If the execution is carried out, the largely Sunni-Arab Baathists said they also will retaliate against members of the Iraqi High Tribunal
And they vowed a complete shut-down of peace negotiations between the Baathists and coalition forces.

The Baathists have been operating as part of the insurgency against the U.S. and its allies since Hussein's regime fell in 2003.

Hussein was convicted November 5 in an Iraqi court of crimes against humanity.

He was sentenced to death by hanging for ordering the killings of 148 people in the predominantly Shiite Muslim city of Dujail in 1982.

The former dictator's execution, upheld by an appellate chamber of the Iraqi High Tribunal, could be carried out any time over the next few weeks
The Baathist message went on to call Hussein's execution a "most dangerous red line" that the Bush administration shouldn't cross.

"The entire world knows that the final decision is in the hands of the American administration and not the agent government in Baghdad," the message said.

The execution "will make later negotiations between the resistance and the Baathists" and the U.S. "impossible." It would further embolden and strengthen the resistance, the message warned.

The Baathists also issued a warning to Iran, which is regarded as a key supporter of Iraq's Shiite-led government.

The Baathists believe that the government and Iran are behind sectarian killings of Sunni Arabs.
The Baathists are asking Iran's "real leader" -- a reference to Supreme Leader Ayatollah Ali Khamenei -- "to be rational and study this matter and not to spill more Iraqi blood, because our retaliation will be in the heart of Iran and impact its leadership."

The Baathists also warned that there will be "no safe place" for Iraqi High Tribunal jurists and those who protect them, calling them "traitors" and "tools for the occupation."