Sectarian hatred has intensified in recent weeks with bomb attacks on Shias and the assassination of many Sunnis.
Zarqawi said in a tape broadcast on the internet that his organisation was setting up a special unit, the Omar Brigade, to combat the Shia Badr Brigade. This militia, once based in Iran, has been accused of operating death squads against former Baathists and Sunnis. The al-Qa'ida leader also said that the Iraqi army was just as much an enemy as the Americans.
Even as his words were broadcast on television in Baghdad there was a series of attacks on the police special commandos, a paramilitary unit in which the Badr Brigade is increasingly influential.
Captain Hazim Jabber and two other commandos were assassinated in separate incidents. Nine other policemen, including a brigadier general, were wounded. In southern Baghdad a member of the Badr Brigade was killed.
A few hours later the commandos, dressed in their distinctive camouflage uniforms and with black balaclavas hiding their faces, staged a dramatic funeral for the dead officers in west Baghdad. With coffins draped in the Iraqi flag strapped to the top of their trucks they drove through west Baghdad firing their machine-guns into the air and bringing traffic to a halt.
The two-million-strong Sunni community in the capital feels increasingly threatened by police and army raids on their districts. There are mass round-ups and arrests of men, many of whom later say they have been beaten and tortured. Eyewitnesses say the assaults on Sunni neighbourhoods are leading to growing support among Sunni for the resistance groups.
Members of the Badr Brigade, the military wing of the Supreme Council for Islamic Revolution in Iraq (SCIRI), are frequently found among the security forces controlled by the interior ministry and in the army. The brigade fought on the Iranian side in the Iran-Iraq war in 1980-88 and was trained by the Iranian Revolutionary Guards.
Bayan Jabr, a member of SCIRI, is the interim Interior Minister, but Hadi al-Amery, the head of Badr, is influential within the ministry.
The spread of the conflict was shown by a recent demonstration by 3,000 Sunnis in the city of Tikrit. They were protesting at the arrest of Colonel Muzhir Taha al-Ghannem, the provincial police chief. He is accused of investigating pro-Iranian Iraqis during the Iran-Iraq war, which would have included the Badr Brigade. The demonstrators threatened to cut electricity and water supplies to Baghdad if he was not released.
The militiamen of the Shia and Kurdish parties, often nominally belonging to the Iraqi army or security forces, are becoming more dominant in the streets of Baghdad. A large notice on 14 July Street says it has been renamed Badr Street. Near by, militiamen of the Patriotic Union of Kurdistan protecting President Jalal al-Talabani's headquarters do not speak Arabic and stop traffic by simply pointing their rifles at the heads of drivers.
The US has been rapidly expanding the Iraqi army and security forces so as to reduce the role of American troops, but the units most willing to fight are drawn from the Kurdish and Shia militias, and feared by Sunnis.
Most of the young army and police recruits killed in the suicide bombing campaign orchestrated by Mr Zarqawi's movement are Shia. There have also been devastating attacks on crowds of pilgrims in the shrine cities of Kerbala and Najaf and against Shia mosques.
Kidnappers of Egypt's top diplomat in Iraq threatened to kill him because Egypt has allied with "Jews and Christians", a statement posted on an al-Qa'ida-linked website with connections to Zarqawi, said.Reuse content