Speaking out strongly in his weekly address on Wednesday, Mr Maliki, from Iraq’s Shiite Arab majority, described the idea of involving Sunni Arabs and Kurds in a more inclusive, power-sharing government as a “coup against the constitution and the democratic process”.

But as he spoke, violence continued to paralyse the country.

A suicide attack on an outdoor market in the Mahmoudiya area, about 30 kilometres south of Baghdad, killed at least 13 people and injured 25, Iraqi police and hospital officials told the Associated Press, while there was another suicide attack in the oil-rich city of Kirkuk in the north.

Militants also launched an attack on an Iraqi Army air base north of Baghdad, while the battle between fighters from the Islamic State of Iraq and the Levant (ISIL) and security forces over control of Iraq’s largest oil refinery in Baiji is ongoing.

Inside the Iraqi Army’s Baghdad Operations Command, spokesman General Saad Maan Ibrahim unfolds a map to point out the major ISIL threats to the so-called Baghdad Belt surrounding the capital.

"The greatest danger is to the south and the west, between the farmlands in Babylon Province and around the farms of Anbar,” he says.

“We have changed from protecting [the capital] to attacking our enemy … our aim is to not give them a chance to step one metre into Baghdad.”

He says the first of up to 300 American advisers have arrived in the capital where they are establishing a joint operations centre – a welcome arrival for the Iraqi military which has been slow off the mark to mount any opposition to the Sunni insurgency.

Air strikes were the next obvious step, he says, given US drones are already in the skies above Iraq and air support was vital to stopping the militants' progress.

“ISIL are now trying to start a branch in Jordan, so it is not just Syria and Iraq, and in the future they may try to operate in Turkey – it is important for the world to help us win this war.”

There was no immediate comment from the US on whether air strikes were imminent, although a spokesman confirmed US drones were flying 30-35 sorties per day.

Iraq’s Anbar province has already come under attack from air strikes, reportedly from Syrian fighter jets on a cross-border raid that killed up to 57 civilians and wounded 120 more.

Syrian state media denied its air force was responsible for the attacks along Iraq’s western border but officials from Anbar say local residents spotted Syrian details on the planes using telescopes and other equipment.

Initial reports from Iraqi state media suggested the attacks had been carried out by US drones, a claim that was quickly denied by the Pentagon.

In Brussels, US Secretary of State John Kerry refused to characterise Mr Maliki’s rejection of a unity government as a snub, saying Washington had not raised the issue with him specifically.

Mr Maliki insisted the results of the April 30 elections – in which his party won the most seats but not an outright majority – should be implemented.

Anything else, he said, “is an attempt by those who are against the constitution to eliminate the young democratic process and steal the votes of the voters".

Meanwhile, the UN confirmed that more than 1000 people had been killed in Iraq in the last two weeks since the Sunni insurgency – led by ISIL but backed by other groups – began.

Another 1000 were injured, although the UN warned the numbers should be viewed “very much as a minimum”.

The violence had included beheadings and shootings of soldiers and police officer by ISIL as well as abuses by Iraqi Security Forces that have included two summary executions of prisoners, the UN said.

Along with the increased security around a city already surrounded by blast walls and checkpoints, the Maliki government intensified its crackdown on opposition media.

Three Egypt-based Iraqi TV stations - al-Baghdadiya, al-Rafidain and al-Hadath - were closed as a result of pressure from the Iraq government, Reporters Without Borders said.

The channels have been accused of broadcasting reports that “attack the security forces and Iraqi national unity”. Their closure comes just two weeks after Jordanian police raided and closed another Iraqi station broadcasting from Amman.