Malcolm (l) and Vernon Wood plead for the life of their brother Douglas

The family of an Australian man held hostage in Iraq has issued a new appeal for his release after masked militants issued a three-day ultimatum for Australia to pull its troops from Iraq.

The brother of 63-year-old hostage Douglas Wood said Saturday the family is "shocked and horrified" about the ultimatum, and says such a demand will not make any difference to Australia's policy of refusing to negotiate with terrorists.

Arabic television al-Jazeera aired a new videotape Friday of Mr. Wood pleading for his life, and of his captors demanding Australia start withdrawing troops within 72 hours.

Mr. Wood - an engineer who has been living with his American wife in the U.S. state of California - has had his head shaved since a video last Sunday issued by his captors, the Shura Council of the Mujahideen of Iraq two days after authorities believe he was abducted.