BAGHDAD, (Reuters) – Gunmen attacked a Sunni Arab neighbourhood of Baghdad and burned mosques on Friday in apparent retaliation for the bloodiest bombing in more than three years of war that killed 202 in a Shi’ite area.

Two suicide bombs ripped through a Shi’ite market in northern Iraq killing 22 people earlier on Friday and mortars crashed on rival Baghdad neighbourhoods, ramping up sectarian tension that threatens to push Iraq into all-out civil war.

As political leaders on all sides pleaded for restraint and imposed a curfew on the capital, gunmen stormed a Sunni enclave in a largely Shi’ite area, burning four mosques and homes, an Interior Ministry official said.

The official said the number of casualties was not known, but a resident of Hurriya district, Imad al-Din al-Hashemi, said at least 18 people had been killed and 24 wounded.

“They attacked four mosques with rocket-propelled grenades and machinegun fire. The attacks began at midday,” said Hashemi, a university academic, who was helping evacuate people.

Among the dead were two women and a child who died of smoke inhalation in burning houses, he said.

The Interior Ministry official said at least two of the mosques had been attacked by rocket-propelled grenades.

Residents were appealing for firefighters and ambulances but the area was too dangerous for police to send reinforcements.

Defence Ministry Spokesman Mohammed al-Askari said there were clashes around midday and the army had intervened, and he denied mosques had been attacked.

Many see a bleak future. “The situation is now moving to some sort of open civil war,” said Iraqi security analyst Mustafa Alani of the Gulf Research Center in Dubai.

The Shi’ite faction that controls Baghdad’s Sadr City slum, target of Thursday’s bombing, demanded the prime minister cancel a summit next week with U.S. President George W. Bush.

Moqtada al-Sadr, the young cleric whose Mehdi Army militia dominates Sadr City, told chanting supporters in a Friday sermon that the most prominent religious figure from the Sunni minority must issue a fatwa demanding an end to the killing of Shi’ites.

One of Sadr’s top political aides in parliament told Reuters it would pull out of the U.S.-backed national unity government and from parliament if Shi’ite Prime Minister Nuri al-Maliki went ahead with next week’s meeting with Bush in Jordan.

Bush is expected to discuss with Maliki ways of giving Iraqi security forces more control to raise the prospect of U.S. troops starting to withdraw. But the competence and loyalties of the U.S.-trained Iraqi forces are in grave doubt.

Maliki is under pressure from an increasingly anxious Washington to make good on promises to disband Sadr’s and other Shi’ite militias, which U.S. officials say control parts of the police and army. But the prime minister is dependent on Sadr and his fellow Shi’ite Islamists to maintain his position.

Sadr, whose Mehdi Army rose up twice in 2004 against U.S. forces, has long demanded their withdrawal and seemed to be seeking to capitalise on the carnage in his Baghdad stronghold to press his case. Another 250 were wounded in the series of six car bombs and several mortar blasts late on Thursday afternoon. He called for restraint from his followers, although similar public statements after the bombing of a major Shi’ite shrine at Samarra in February failed to prevent reprisal killings, much of which Sunni leaders blame on the Mehdi Army.

Many Sunnis, the dominant minority under Saddam Hussein and the source of the long insurgency against U.S. occupation, now fear a rapid withdrawal of the 140,000 American troops could unleash an all-out offensive by Iranian-backed Shi’ite militias.

In the western Sunni bastion of Falluja, cleric Khaled Mohammed told worshippers at Friday prayers: “I call on the people of Falluja to send money, food and clothes to our brothers in Sadr City and Adhamiya — we have a common enemy who attacked them to spark sectarian strife between us.”