[Does someone fear nonviolent protests more than shooting?]
Iraqi Shiite cleric Moqtada al-Sadr has threatened to lift a ceasefire of his Mehdi Army militia while indefinitely postponing a mass anti-US demonstration.
Despite the ceasefire which Sadr called last August, his followers have clashed with Iraqi government troops and US forces in the south of the country and Baghdad in recent weeks, leading to Iraq's worst violence since the first half of 2007.
"If it is required to lift the freeze (ceasefire) in order to carry out our goals, objectives, doctrines and religious principles and patriotism, we will do that later and in a separate statement," he said in a statement on his website.
He postponed indefinitely a "million-strong march" called for Wednesday to coincide with the fifth anniversary of the fall of Baghdad, which had raised the prospect of unrest coinciding with testimony in Congress by the top US officials in Iraq.
"I call those beloved Iraqi people who wish to demonstrate against the occupation to postpone their march, out of my fear for them and my concern to spare their blood," Sadr said.
"I fear that Iraqi hands will be lifted against you, although I would be honoured if the Americans were to lift their hands against you," he said.