BAGHDAD -- Thousands of Shiites from Baghdad and across southern Iraq answered an urgent call to arms Saturday, joining security forces to fight the Islamic militants who have captured large swaths of territory north of the capital and now imperil a city with a much-revered religious shrine.
The mobilization, urged by the nation's top Shiite cleric, took on a sectarian dimension that threatened to intensify Sunni-Shiite strife in a nation already ripped by religious fervor after the militants' battlefield successes.
In Baghdad, fallout from the stunning advance in the north was beginning to affect daily life for the city's 7 million inhabitants.
Some food prices rose dramatically. Army troops went house-to-house searching for militants and weapons in neighborhoods close to vital government installations. The streets of the capital were quieter than usual, and military and police checkpoints made extra efforts to check cars and passenger IDs.
The price hikes were partly the result of transportation disruptions on the main road linking the capital with provinces to the north, but they might also be a telltale sign of a nervous city.
In the meantime, dozens of men climbed into the back of army trucks at volunteer centers, chanting Shiite religious slogans, hoisting assault rifles and pledging to join the nation's beleaguered security forces to battle the Sunni militants of the Islamic State of Iraq and the Levant, or ISIL.
"By God's will, we will be victorious." said one volunteer, Ali Saleh Aziz. "We will not be stopped by the ISIL or any other terrorists."
The volunteers were first taken to an assembly center in eastern Baghdad, where they were handed military uniforms, and later went to Taji, home of Iraq's largest military base north of Baghdad, to undergo basic training. State-run television aired footage of the volunteers being drilled, still in their civilian clothes.
The mobilization unfolded against a backdrop of religious and nationalist fervor. State-run television aired a constant flow of nationalist songs, clips of soldiers marching or singing, as well as interviews with troops vowing to crush the militants. Other broadcasts included archival clips of the nation's top Shiite clerics and aerial shots of Shiite shrines.
As President Barack Obama considers possible military options for Iraq, Defense Secretary Chuck Hagel ordered the aircraft carrier USS George H.W. Bush to move from the northern Arabian Sea into the Persian Gulf. The carrier was to be accompanied by two guided-missile ships.