A six-month-old cease-fire agreement by Shiite cleric Moqtada al-Sadr and his feared Mahdi Army could run out by the end of the week.
Sheik Salah al-Obeidi, al-Sadr's chief spokesman, speaking from the holy city of Najaf, told ABC News the cease-fire is due to end Sunday, but he said there's still a chance it could be extended beyond that if the powerful cleric desired.
The militia has been widely credited with helping to create an atmosphere of relative calm in Iraq.
"If al-Sadr does not make a statement extending the cease-fire before Sunday, then it will be finished," al-Obeidi said. "But all possibilities are still open."
Al-Obeidi made no direct threats to ABC News that al-Sadr would not extend the cease-fire and it's hoped by many in Iraq that the lull in the fighting will continue.
The Mahdi Army is one of Iraq's most influential and powerful militias and it was ordered by al-Sadr to halt hostilities in late August after dozens of people in the holy city of Karbala were killed in gun battles among rival Shiite factions.
He vowed to eject rogue members blamed for much of the infighting and to reorganize the militia, which had also been blamed for much sectarian fighting in Baghdad.
The U.S. military says the cease-fire helped bring violence down sharply in the latter part of 2007, calling it a major factor in the estimated 60 percent decline in violence in the country.
"Moqtada al-Sadr's cease-fire has been helpful in reducing the violence and has led to improved security in Iraq," Lt. Michael Street, a U.S. military spokesman in Baghdad, told ABC News. "We welcome an extension of the cease-fire as a positive step by al-Sadr."
If the cease-fire is allowed to expire, hundreds of gun-toting gunmen would most likely take to the streets again throughout the Shiite majority areas of Baghdad and southern Iraq.
"During the past few months many Mahdi Army militia members put their guns away and got back to their normal lives," a resident of Sadr City, Baghdad's Shiite majority neighborhood, told ABC News.
"But without the cease-fire things will go right back to the way they were six months ago. There will be gunfire on the streets again because militia fighters will respond to any attacks against them." he said.
Despite the suspension of hostilities by al-Sadr's fighters, the U.S. military — alongside allied Iraqi army troops — has insisted on continuing to stage raids against what it calls "special groups" of Iranian-backed breakaway factions of the Mahdi Army.
Some influential members of al-Sadr's movement have been urging him to call off the cease-fire when it expires.
Al-Sadr's followers claim the U.S.-Iraqi raids, particularly in the southern Shiite cities of Diwaniyah, Basra and Karbala, are a pretext to crack down on the wider movement.