More than 55 people were killed in three car bomb attacks across Iraq today, including two blasts near restaurants filled with lunchtime crowds in Sunni Arab cities that had been relatively calm.

In one of the deadliest moments in months, a car bomb exploded outside a courthouse and the offices of the provincial government in Baquba, the capital of Diyala province, north of Baghdad, leaving at least 40 dead and another 80 wounded. A busy restaurant was also close by.

The sheer number of victims, among them women and children, left emergency services struggling to cope. Dr Ahmed Fuad, at a local hospital, said that most of the dead were "burnt beyond recognition".

One witness described seeing a huge fire that sent black smoke billowing into the sky. Passing cars were set ablaze, trapping drivers and their passengers in a deadly inferno. Several stores and the restaurant were badly damaged, with glass strewn across the street.

The US military condemned the bombing, which it said killed 36 and wounded 67, but emphasised that the security situation was improving. "This is the first suicide attack inside Baquba in almost 90 days, and the overall violence in the city has decreased by 80 per cent since June,” Major Mike Garcia said.

US and Iraqi forces have been pushing into Diyala since the start of the year after commanders said that successful operations in and around Baghdad had forced al-Qaeda militants to move northwards.

Underscoring the fragility of the gains, however, a suicide car bomb shattered a fragile peace that had settled across Ramadi, the capital of central Anbar province, once a notorious hotbed of the al-Qaeda insurgency. At least 13 people were killed and a further 14 people were wounded in the blast that went off outside a kebab restaurant west of the city centre.

Baghdad was also shaken after a car bomb targeting a police patrol left three people dead and eight injured.

It was not immediately clear whether the triple bombing was random or part of a co-ordinated campaign.

In addition, at least 12 people were wounded when twin car bombs exploded in quick succession as a US military and Iraqi patrol in Iraq's main northern city of Mosul. The wave of violence followed a suicide attack and two car bombs that killed 18 people in northern Iraq yesterday.

Problems in the north have largely been overshadowed in recent weeks by clashes between security forces and the al-Mahdi Army militia in Shia-predominated southern Iraq and also the capital.

Operations are continuing in Basra, where the British hostage Richard Butler was rescued from a house by Iraqi soldiers yesterday after two months in captivity. The photojournalist, who had been on assignment for the American television network CBS News, has since been flown out of Iraq to an undisclosed location.

Security forces are also battling armed gangs in the Baghdad Shia slum of Sadr City, an al-Mahdi Army bastion. Police said six people died and 26 were wounded in clashes overnight. The US military said it had killed at least 10 fighters.

Sunni Islamist al-Qaeda has suffered a drop in support over the past year as thousands of fighters switched allegiance and signed up to work as security guards in their neighbourhood under the payroll of the US military. The move helped to produce a dramatic decline in attacks in one-time trouble spots such as Anbar province.

In a bid to return to the status quo, the purported leader of a group affiliated with al-Qaeda in Iraq urged the Sunni militants who had rebelled against the extremist group to return to the fight. In a 30-minute internet recording, Abu Omar al-Baghdadi said: “The scholars of the faith and the honorable sheiks of the tribes are charged with calling and urging the children of the Sunni sheikdoms to leave the army and the police ... and the Awakening Councils, on the basis that all arms ... be directed at the Crusaders and those who support them.”

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