Iraqi armed forces

After Iraq's armed forces were disbanded following the fall of Saddam Hussein in 2003, the United States and its allies committed more than $25bn to training and building a new military. With more than 250,000 frontline troops (not counting paramilitary police units), on paper at least the Iraqi military should be effective. It is equipped with almost 400 tanks including US M1A1s and Russian T- series tanks including the T-72. It also has more than 2,500 armoured fighting vehicles and 278 aircraft, including drones, transport aircraft, amphibious aircraft and 129 helicopters.

But despite its manpower and equipment – and the huge sums invested in it – the Iraqi military has suffered constant problems with combat readiness at battalion level while struggling to attract sufficient recruits to maintain effectiveness, particularly in key areas such as training. As the security environment in Iraq has steadily worsened, the government under the prime minister, Nouri al-Maliki, has tended to concentrate elite units in the capital, while recent operations in the west on the Syrian border and around Falluja and Ramadi have suggested both serious political and operational shortcomings. The collapse of an estimated 30,000 forces in and around Mosul underlined a lack of morale and an apparently chaotic chain of command.

Isis

Estimates put the fighting strength of Isis in Syria and Iraq at around 7,000 but its numbers in Iraq appear to have been bolstered by other groups, including local Sunni militants and Ba'ath nationalists particularly in Tikrit. Despite claims that they have captured helicopters in Mosul, it seems unlikely they would be able to deploy them. Lightly armed with Toyota pickup technicals, RPGs and small arms, Isis has captured some armoured Humvees, although there are suggestions that some equipment has been sent back to Syria. While they have been able to operate easily in largely Sunni areas where they have some support from a population angry and alienated from the Shia-led government in Baghdad, the capital is a different proposition. One district alone, Sadr City, has a Shia population of some 1 million and since the sectarian war that ended in 2008, the sprawling suburbs have been divided along sectarian lines with checkpoints and barriers.

Peshmerga

Although some 35,000 Kurdish peshmerga are incorporated into the Iraqi security forces, other peshmerga remain outside with published estimates varying from 80,000 to three times that number. Two years ago a Kurdish official suggested the peshmerga numbered 190,000. Increasingly well equipped – including with 2,000 armoured vehicles and rocket artillery systems – they are regarded as motivated, well trained and experienced.