Earlier in the week, the president of Iraq's autonomous Kurdish region had banned the national banner from the north of the country.

The latest dispute over the national banner came amid a wave of violence between Iraq's warring Shiite and Sunni communities that has left more than 400 people dead in the past week, including 14 south Asian pilgrims.

"The present Iraqi flag should be hoisted on every inch of Iraqi soil until the parliament takes a decision about it," Maliki said in a statement issued by his office.

Massud Barzani, president of the Kurdish region in northern Iraq, last week raised separatist tensions after he banned the Iraqi flag from government offices in the region, leaving the Kurdish colours to fly alone.

Barzani's order said: "Regions in Iraq's Kurdistan which have been hoisting the Baathist flag should lower it and hoist only the Kurdistan flag".

Iraq's Kurdish minority associates Iraq's red, white and black banner with ousted president Saddam Hussein's hated Baath party, although it has been retained as the national flag by the post-Saddam government in Baghdad.

On May 7, the Kurdish administrations of Arbil and Sulaimaniyah provinces were united with one parliament and government for the whole of the northern Kurdish region, which enjoys broad self-rule.

Before unification some official buildings in the Sulaimaniyah region -- which was ruled by Iraqi President Jalal Talabani's Patriotic Union of Kurdistan (PUK) -- used to hoist the Iraqi flag along with the PUK party flag.

Barzani's Arbil administration never hoisted the Iraqi colours.

Barzani, the current leader of the Kurdish region, said last year that the Iraqi flag "dates back to 1963 since when many pogroms and mass-killings were committed in its name.

"Therefore, it is impossible to hoist this flag in Kurdistan."

Iraq's Kurdish minority has enjoyed wide autonomy ever since Saddam's defeat in the 1991 Gulf War over Kuwait and strongly supported the 2003 US-led invasion which unseated him.

But Kurdish leaders have reconsidered demands for independence while supporting Maliki's government of national unity.

The latest controversy comes a day after Iraq's revered Shiite cleric Grand Ayatollah Ali al-Sistani urged Maliki to quell the raging sectarian conflict or face the dangers of rampaging militias.

"His eminence said when the government fails to do its duty in providing security, order and protection for citizens, this could pave the way for other powers to intercept and carry out this mission," Sistani's office said.

Sistani was alluding to the rise of Shiite militias, such as the Mahdi Army of radical cleric Moqtada al-Sadr and the Badr Organization of the Supreme Council for the Islamic Revolution in Iraq (SCIRI), a leading religious party.

As if in response to the latest dialogue between the two leaders, gunmen killed Sunday an aide of Sistani in the southern city of Amara, police said.

Sheikh Hassan Mohammed Mahdi al-Jawadi, 56, was gunned down in front of his office by gunmen in a car, two weeks after his son, a policeman, was also killed.

On Saturday a group of pilgrims from south Asia also fell prey to Iraq's Shiite-Sunni conflict.

Suspected Sunni gunmen dragged a group of 11 Pakistani and three Indian travellers off a bus crossing the desert towards the Shiite holy city of Karbala and shot them dead.

Meanwhile, the inauguration of a new Iraqi joint military command has been postponed because of a disagreement about how to define its relationship with US forces deployed in the country, a US military spokesman said.

"The ceremony was postponed in order to clarify language in the memorandum that delineates coalition support and responsibilities to the new Iraqi Joint headquarters," Lieutenant Colonel Barry Johnson said.

"The major points and substance of the agreement are not in question. However, there is specific wording that needs to be refined," he added.

Once it is up and running, the new Iraqi headquarters will gradually assume operational command of Iraq's 115,000-strong army, which is currently overseen by US headquarters.