(Adds background) LONDON, Dec 30 (Reuters) - Saddam Hussein's Baath Party urged Iraqis to "strike without mercy" at U.S. occupiers and Shi'ite Iran to avenge the execution of Iraq's former president but warned them not to be drawn into a civil war. "Today is your great day. Strike without mercy at the joint enemy in Iraq -- America and Iran," the party believed to be spearheading an anti-U.S. insurgency in Iraq said in a statement posted on the Internet on Saturday. "Forget your organisational structures and take the stand of honour you deserve which is to take revenge for Saddam Hussein," said the statement, posted on the Web site www.albasrah.net. Its authenticity could not be immediately verified. The statement came shortly after Saddam was hanged at dawn on Saturday for crimes against humanity, more than three years following his overthrow by U.S.-led forces. His execution on the first day of the Muslim Eid al-Adha feast came after a court convicted him over the deaths of 148 Iraqi Shi'ites in the town of Dujail following a 1982 assassination attempt. Saddam's execution has further divided Iraqis, with Iranian-backed majority Shi'ites who suffered under him rejoicing at his death, while his fellow Sunnis voiced anger. Iraq's U.S.-backed government blames Saddam supporters for much of the violence in Iraq. Baathists say their attacks are concentrated on U.S.-led forces with the aim of ending the occupation. The pan-Arab Baath Party, which ruled Iraq for more than 30 years until Saddam's fall but is now banned, warned followers to avoid harming fellow Iraqis. "Let your destructive response be by stepping up jihad (holy struggle) against the occupation and against Iran," said the statement. "Our revenge from America and Iran is in defeating the occupation and causing it bigger losses," it said, noting that Iranian, Israeli and U.S. leaders were first to celebrate Saddam's execution. Saddam had fought an eight-year war against Iran in the 1980s. His Baath party holds clerical rulers of Shi'ite Iran and the United States responsible for sectarian violence that has brought Iraq to the brink of civil war between Sunnis and Shi'ites.
