18 June 2014
Last updated at 05:52
Residents of the Iraqi capital, Baghdad, are stockpiling food and water as Islamist militants move closer.
Fighting between ISIS and the security forces, supported by Shia militias, has raged around the city of Baquba, only 60km (35 miles) away from the capital.
Correspondents say that the capital is tense with the the insurgents closing in from the north and from the west.
Iraqi forces have been engaged in heavy clashes with the rebels who have seized several key cities in the past week.
UK Prime Minister David Cameron will hold talks with his senior security advisers on Wednesday to discuss the crisis, warning that ISIS represented “a real threat to our country”.
Iraqi Prime Minister Nouri Maliki has fired senior officers for failing to halt the sweeping advance by Sunni Islamist rebels.
In unusually strong language on Tuesday, he has accused Saudi Arabia – which is largely Sunni – of backing ISIS.
With Shia areas of the capital bombed almost daily, correspondents say that inhabitants of Baghdad have developed a siege mentality.
People with enough money have started to stockpile essential items of food, correspondents say, which has increased prices dramatically.
The government has insisted that food supplies are not in danger and that ISIS will not be able to take Baghdad
Prices of food and other essential items have risen significantly in and out of Baghdad as the conflict has escalated
The army and Shia militiamen (pictured) have been showing their strength in Baghdad as the city braces itself for a possiblke ISIS attack
Correpondents have warned that Iraq could be on the brink of outright sectarian war between Sunnis and Shias
Four army commanders were dismissed because they did not perform “their national duty”, a government statement said on Tuesday.
Mr Maliki and other senior figures of his Shia government were joined by Sunni leaders in a call for “national unity”, after talks in Baghdad on Tuesday evening.
They urged Iraqis to avoid sectarian grievances and said individuals with no official state function were banned from carrying weapons.
The militants, led by the Islamic State in Iraq and the Levant (ISIS), took control of the northern cities of Mosul and Tikrit in a rapid advance last week, and Tal Afar on Monday.
They also briefly captured parts of the city of Baquba – just 60km (35 miles) from Baghdad – in an overnight assault, before government troops and allied Shia militia pushed them back on Tuesday.
Qasem Suleimani, the commander of an elite unit of Iran’s revolutionary guards, is reported to be in Baghdad, helping military and Shia leaders co-ordinate their campaign against the rebels.
Analysis: John Simpson, BBC World Affairs Editor, Baghdad
Many Sunnis, particularly the conservative ones who started turning against al-Qaeda eight years ago, and enabled the US forces to leave Iraq with what seemed at the time to be dignity, are not at all happy that ISIS should control their towns and villages.
But the danger of the present fight-back by Shia volunteers is that they will victimise ordinary Sunnis, and make them feel that ISIS is the only group that can protect them.
In other words, this has the potential to turn into a clear-cut religious war, with the possibility of mass “cleansing” of civilians and brutality on a large scale.
The Iraqi officers fired on Tuesday include the top commander for Nineveh, the first province where ISIS fighters made major gains.
In other developments:
- President Obama will brief top congressional leaders on Irag at the White House on Wednesday
- The US is considering the possibility of deploying a small number of special operations forces to Iraq to help train security forces, officials have told the AP news agency
ISIS in Iraq
The rebels now control the northern cities of Mosul and Tikrit
ISIS grew out of an al-Qaeda-linked organisation in Iraq
- Estimated 10,000 fighters in Iraq and Syria
- Joined in its offensives by other Sunni militant groups, including Saddam-era officers and soldiers, and disaffected Sunni tribal fighters
- Exploits standoff between Iraqi government and the minority Sunni Arab community, which complains that Shia Prime Minister Nouri Maliki is monopolising power
- ISIS led by Abu Bakr al-Baghdadi, obscure figure regarded as a battlefield commander and tactician
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