BAGHDAD, Feb 23 (Reuters) When Hussein Ali was stopped at a makeshift checkpoint in Baghdad, gunmen asked a question he never feared before the bombing of a sacred shrine yesterday sparked a wave of violence -- are you Shi'ite or Sunni? ''One of the gunmen looked at my identification card,'' Ali, motorcycle courier, said today. ''He let me pass because I am Shi'ite. But I told him there was no difference between Shi'ites and Sunnis.'' Many Iraqis would like to believe that. But the devastation of a major Shi'ite shrine in Samarra north of Baghdad is making it very difficult.
No single act of violence has fired as much fear of civil war as the attack on the Golden Mosque yesterday, even bombings that have killed more than 100 people at a time.
Iraqis pointed their fingers in familiar directions, accusing the United States, Israel, Iran, Arab countries and al Qaeda of trying to tear their country apart.
But sectarian anger is boiling beneath the surface and people who had dismissed talk of civil war after past crises no longer rule it out.
SYSTEMATIC KILLINGS? Police said 130 people were killed in Baghdad in the 24 hours after the blast. That casualty figure was not high by Iraqi standards but signs emerged that sectarian killings might be becoming more systematic.
Hours after the Samarra blast, Shi'ite gunmen showed up at the Baghdad home of a 55-year-old Sunni woman, relatives said.
Word about the explosion had spread like wildfire so there was little doubt they had come for revenge.
Neighbours pleaded with the gunmen and tried to convince them she was a Shi'ite. She was killed minutes later and her son was kidnapped.
''The gunmen told her that they knew she was a Sunni from Samarra. They shot her three times in the head,'' the relative said.
Other Iraqis are not taking any chances as militiamen roam the streets, defying police and security forces.
Sunnis sawed down palm tree trunks in the Amiriya district of the capital and used them to block off roads leading to mosques.
In Adhamiya, cars packed with Sunni insurgents patrolled the streets while their comrades stood guard in front of mosques.
An army officer, who said he was under orders to protect Shi'ite and Sunni mosques, acknowledged it could be difficult in such sensitive times.
''We are trying to pacify the situation in spite of the fact that some of the mosques are under the control of gunmen but we do not want to confront them so as not to ignite the situation,'' said the officer who asked not to be named.
Iraqis have heard several appeals for calm from their government.
But they are getting mixed signals every time they turn on their televisions.
Government-run Iraqiya television included in its schedule a graphic video hailing 9th-century Shi'ite leaders' battles against Sunni dominance set against the backdrop of images of the devastated shrine.
One Iraqi man stood silently inside a gutted Sunni mosque staring at charred walls that can no longer protect him.
Reuters SRS GC2152