Iraq's Prime Minister said Sunday that the country's army has been paying salaries to at least 50,000 soldiers who do not exist, the latest sign of corruption in a force that the U.S. hopes to help contain the Islamic State militant group.

Iraqi Prime Minister Haider al-Abadi told the country's Parliament that the practice was revealed as part of a preliminary investigation, and that further probes would likely show "more and more" false names.

"Ghost soldiers" refer to people whose names appear on military rolls and who are paid salaries, but are not in military service. The Washington Post reported that the practice is often carried out by officers, who pretend to have more soldiers on their books then they really do and pocket the extra salary.

The Post reported that an entry level soldier in the Iraqi army receives a salary of approximately $600 per month. If the 50,000 figure is accurate, the "ghost soldiers" are costing Iraq's treasury at least $350 million per year. However, Iraqi officials say that the true number of false names could be far greater than al-Abadi reported.

"It could be more than triple this number," Hamid al-Mutlaq, a member of the parliamentary defense and security committee, told the Post. "The people who are responsible for this should be punished. Iraq’s safe has been emptied."

Widespread corruption and mismanagement in the Iraqi army under former Prime Minister Nouri al-Maliki has been blamed for the collapse of four of its divisions this summer in the face of an Islamic State offensive that overran Iraq's second-largest city, Mosul.

The Pentagon has already requested $1.2 billion from Congress to better train and equip Iraq's army to improve its performance against the militants. U.S. officials told the Post earlier this week that the military hoped to build up nine new brigades that could work with Kurdish and Shiite fighters against the Islamic State.

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