Kurdish Peshmerga fighters walk next to their tank as they take control of the area, on the outskirts of Mosul February 6, 2015.
Kurdish Peshmerga fighters walk next to their tank as they take control of the area, on the outskirts of Mosul February 6, 2015.Reuters

There are good indications that the dreaded Islamic State (Isis) group in Iraq and Syria could be on a decline militarily as the US forces plan a massive attack in order to retake Mosul in Iraq, a US military official said on Thursday.

The United States forces are gathering and training about 20,000 to 25,000 Iraqi and Kurdish forces in what is understood to be a preparation for a spring attack aimed at retaking Mosul from the hands of Isis, the group also known by the acronym ISIL. The jihadist group, which overran the city along with a swathe of area north of Iraq and Syria in the summer of last year, have about 1,000 to 2,000 fighters there.

In what appears to be a warning to the extremist group, an official from US Central Command (CENTCOM), which is currently responsible for overseeing the US-led coalition against the hardliners, said in a dramatic briefing to reporters that the US is preparing the massive military composition that the United States hopes will be in the front-line as early as five weeks from now, reports Defense One.

The new coalition attack force would be composed of different sections taking care of strategic defence plans. The force will, for example, have five Iraqi brigades that will require undergoing US training course while three Peshmerga brigades will be responsible for attacking Mosul "from the north". There will also be a group of Musul police officers as well as members of special operation forces of Iraq's Counter Terrorism Service.

According to the official, the US military will most likely begin the operation in April or May. However, it will be delayed if training for the brigades is not completed soon enough, the official said.

"Militarily, ISIL is in a decline," the official said although he didn't provide details on how much land has been regained already from the hardliner Sunnis. According to estimates, the coalition force has taken over 700 to 800 square kilometres ever since the operation began last summer.