“The war is not between the Iraqis and the Americans. It is between the Shia and the Sunni,” Colonel Salem Zajay, a police commander from one of the frontline districts in southern Baghdad, said — on a day when at least 24 people were killed in a string of car bombs in the capital.

The colonel, a Shia with 26 years’ policing experience, oversees one of the roughest areas of Baghdad, the mixed neighbourhood of Doura, where both Sunnis and Shia claim to be victims of systematic sectarian killings.

Having been driven from their stronghold in Fallujah by American forces — backed by mostly Shia Iraqi troops — Sunni guerrillas moved east in November into villages south of Baghdad. In these lush farmlands, Saddam Hussein used to settle loyal officers from his security forces before the war. There they have built new bases, often chasing out “apostate” Shia, whom they revile as American spies. Now they are pushing into Baghdad through Doura, residents say.

“We have lots of information that the Baathists are regrouping,” said the colonel, who bears a livid scar on his cheek from a recent murder attempt. “They think they can take power again.”

Colonel Zajay, who says he cannot trust even some of his own Sunni officers, said that the main targets have been Shia Sayyids, or descendants of the ancient Imams Ali and Hussein. “They will kill any Sayyid in Doura,” he said, but emphasised that hit squads also strike randomly at the Shia community, especially the police. “Many Shia have been attacked, especially in the last two months, and many of them killed.”

The situation has become so chronic that he allows Shias to carry guns on their own streets for self-defence.

Abu Ali, a Shia driver from Doura, recounted how he was sitting in his car with his family, waiting for his son to come out of a shop, when the street erupted in bullets. He sped off to save his wife and children: when the gunfire ended, he ran back to look for his son. The boy was shaken but unhurt, sheltering behind a refrigerator that was pocked with bullet holes. Next door, the pharmacist lay dead in his shop.

“When I asked people why they killed him, they said it was because he was a Shia and had pictures of Imam Ali and Hussein in his shop,” Mr Ali said.

Abu Bakr, a young Shia who fled his home in Doura, said that Sunni gangs had videotaped Shia religious processions and voters in the elections and then murdered those who took part, attacking with impunity in public places.

In response to the violence, a steady trickle of Shias are leaving their homes in Baghdad’s troublespots and heading for the sanctuary of the holy cities of Najaf and Karbala.

While Shias say they are prevented from reprisal by edicts from their religious leaders, Sunnis complain they are also being targeted on a regular basis because of their faith.

Abdul Malik al-Obaidi, 29, a Sunni car mechanic from Hay al-Amal, near Doura, saw his friend shot twice in the leg by a gunman who walked up to his shop and opened fire. Six accomplices told people not to intervene.

“I’m worried that my turn might come soon, so I’m going to close my shop. I feel threatened all the time,” he said. “It’s very hard when you feel you are waiting for death any second. I don’t sit alone in my shop nowadays; I always call a friend to come sit with me.

Some Shia sheikhs affiliated to the militant cleric Hojatoleslam Moqtada al-Sadr have admitted striking at Sunni crime gangs.

In western Baghdad, another pharmacist, an elderly Sunni, was killed recently. Abu Riam received a threatening letter a few days before he was shot, neighbours said. It read: “Leave the area or you will be killed. What the hell is a Sunni like you doing here in such a Shia area?”

When attacked, Sunnis rarely turn to the security forces, which are dominated by Shias and Kurds. Iyad, a local doctor, said that he was rounded up with 80 other Sunnis and beaten by National Guardsmen, who cursed the first Sunni caliphs who succeeded the Prophet Muhammad.

“They took us from homes, and interrogated us like we were real terrorists. The only reason was because we pray at the local Sunni mosque,” he said. “They started by burning our beards, then beat us.”

Sabah Kadhim, an adviser to Bayan Jabbor, the Interior Minister, said that Iraq may already be on the slippery slope to a much-feared internecine conflict.

“I do not want to say civil war, but we are going the Lebanese route, and we know where that led,” he said. “We are going to end up with certain areas that are controlled by certain warlords . . . It’s Sunni versus Shia, that is the issue that is really in the ascendancy right now.”

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