One bomber killed almost 100 people when he blew up a fuel tanker south of Baghdad, an attack aimed at snapping Shia patience and triggering the full-blown sectarian war that al-Qaeda has been trying to foment for almost two years.

Iraq’s security forces have been overwhelmed by the scale of the suicide bombings — 11 on Friday alone and many more over the weekend — ordered by the Jordanian terrorist Abu Musab al-Zarqawi.

“What is truly happening, and what shall happen, is clear: a war against the Shias,” Sheikh Jalal al-Din al-Saghir, a prominent Shia cleric and MP, told the Iraqi parliament.

Sheikh al-Saghir is close to Grand Ayatollah Ali al-Sistani, the supreme Shia spiritual leader and moderate who has so far managed to restrain powerful Shia militias from undertaking any outright attack on Sunni insurgents. His warning suggests that the Shia leadership may be losing its grip over Shias who in private often call for an armed backlash against their Sunni assailants.

The sheikh also cautioned Sunni clerics supporting the insurgency against American forces and the Shia-Kurdish Government elected in January. “I am very keen to preserve the Sunni blood that would be shed due to the irrational acts of some of their leaders, who do not see that they are leading the country into civil war,” he told the national assembly.

On the streets of Baghdad, al-Zarqawi’s al-Qaeda organisation in Iraq unleashed one suicide bomber after another and promised no respite.

“The Hassan Ibrahim al-Zaidi attack continues for the second day in a row, with rigged cars, martyrdom attacks and clashes,” an al-Qaeda internet statement said. “We warn the enemies of God of more to come.” One of the suicide bombers, a Libyan, was arrested at the mass funerals of 32 Shia children killed last week by a car bomber.

But the worst attack occurred in the mixed town of Musaib, in the area south of Baghdad known as the Triangle of Death, when a fuel tanker blew up in a crowded market near a mosque on Saturday evening. The death toll rose to 98 yesterday, making it one the deadliest attacks yet.

Relatives searched the shattered market for the body parts of missing loved ones. “I saw a lot of burnt bodies after the explosion and many people throwing their children from the windows and balconies because the buildings were on fire,” Ammar al-Qaragouli said.

Iraqi soldiers have set up checkpoints to try to rein in the bombers, only to become sitting ducks. Two dozen more people died yesterday in four suicide bombings targeting US and Iraqi security forces.

At least one desperate parliamentarian called for the population to form local militias to defend their neighbourhoods — a move that many see as prelude to a sectarian war.

“The plans of the Interior and Defence ministries to impose security in Iraq have failed to stop the terrorists. We need to bring back popular security committees,” Khudair al-Khuzai, a senior parliamentarian who claimed that 50 fellow MPs supported him, said. But with the streets of Baghdad seething with fear, anger and rumours of impending conflict, confidence in anything that the Government says has plummeted. A poll in the state-sponsored al-Sabah newspaper indicated that 51 per cent of Iraqis see the Government’s performance as weak, while only 32 per cent approved. Fuelling the sectarian tension, leaflets are being distributed in southern Baghdad threatening named Shia “collaborators” with execution. Increasingly hardline Shia militias, such as the outlawed Mahdi Army of the cleric Moqtada al-Sadr, are patrolling large parts of Baghdad, often rounding up suspected Sunni insurgents and imprisoning or even killing them. With the country in turmoil, much of the Government, including Ibrahim al-Jaafari, the Shia Prime Minister, was on a landmark trip to try to repair relations with Iran, where President Khatami hailed a “turning point” in relations between the neighbours. He promised that his country would do all in its power to rebuild Iraq. But closer ties with Iran’s Shia theo- cracy has alarmed Iraqi Sunnis, who accuse Iran of interfering.

John Reid, the British Defence Secretary, told CNN yesterday that Britain could start to reduce its troop levels in Iraq over the next 12 months. He said that neither Britain nor America had any imperialist ambitions and were anxious that Iraqi forces should assume responsibility for security.

Mr Reid spoke as a report issued yesterday by Chatham House and the Economic and Social Research Council, two British think-tanks, said that British lives had been lost in Iraq and elsewhere because it was seen as “riding pillion” with the United States.

The Iraq war “gave a boost to the al-Qaeda network’s propaganda, recruitment and fundraising, caused a major split in the coalition, provided an ideal targeting and training area for al-Qaeda-linked terrorists and deflected resources and assistance that could have been used to . . . bring (Osama) bin Laden to justice,” it said.

72 HOURS OF VIOLENCE

Friday 10 suicide car bombers kill 26 people and wound more than 100 in apparently co-ordinated attacks on US and Iraqi forces

Saturday At least 107 people killed and 185 injured in 5 suicide bombings, including the fuel tanker explosion that left 98 dead

Sunday Bombers kill 19 and wound more than 14 in 4 suicide attacks around Baghdad