Image copyright AFP Image caption Iraq has become increasingly reliant on Shia militias to help government troops in the battle with IS

US President Barack Obama is reportedly preparing to approve the deployment of more US troops to Iraq to train up local forces fighting Islamic State.

He is considering up to 500 additional troops as well as a new training base in Iraq's Anbar province, unnamed US officials were quoted as saying.

President Obama said earlier this week the US lacked a "complete strategy" for helping Iraq regain territory from IS.

IS has recently made gains in Iraq despite US-led coalition air strikes.

In May the militants seized Ramadi, the capital of Anbar, Iraq's largest province, as well as the Syrian town of Tadmur and the neighbouring ancient ruins of Palmyra.

IS fighters took control of Iraq's second city Mosul a year ago.

Inside Mosul: Life under IS control

On the front line in battle for Mosul

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What has happened since the fall of Mosul?

The US National Security Council said it was now "considering a range of options to accelerate the training and equipping of Iraqi security forces".

"Those options include sending additional trainers," spokesman Alistair Baskey said.

General Martin Dempsey, chairman of the Joint Chiefs of Staff, told journalists on a visit to Jerusalem that there would be no fundamental change to Mr Obama's military strategy in Iraq.

But, he added, the service chiefs had "made some recommendations on potential enhancements to the training and equip mission".

Analysis: Jonathan Marcus, BBC diplomatic correspondent

Sending more US trainers may ultimately help to build a new Iraqi military but for many analysts the problem remains: The US strategy is not so much incomplete, as President Obama admits, but failing.

So how might it be done differently?

General David Petraeus, the architect behind the strategy that helped to defeat Islamic State's predecessor, told me in a BBC interview earlier this month that the US needed to furnish much closer support to the Iraqis both at the government level in Baghdad and on the ground.

He did not rule out sending US forward air controllers to the front line, for example.

And he made it clear that in his view Iraqi troops could fight and win, but they needed to know that the US and its allies "had their back", ie, that air power support was just a call away.

The plan follows months of behind-the-scenes debate within the White House on how to retake Mosul and Ramadi, the New York Times reports.

US officials believe a major factor in the fall of Ramadi was a lack of training of Iraqi forces.

There are currently around 3,000 US military personnel, including trainers and advisers, in Iraq.

The United Kingdom said earlier this week it will send an extra 125 troops, taking the number of UK personnel training Iraqi security forces to 275.

Media playback is unsupported on your device Media caption President Obama: "We want to get more Iraqi security forces trained"

Image copyright AP Image caption President Obama discussed the issue with Iraqi Prime Minister Haider al-Abadi on the sidelines of the G7 summit

Mr Obama said on Monday that the US did not have a complete strategy in Iraq "because it requires commitments on the part of Iraqis as well about how recruitment takes place, how that training takes place".

He said that US staff in Iraq sometimes found themselves with "more training capacity than we've got recruits".

Mr Obama said it was important to draw Sunni Muslims into the fight against IS as they are "willing and prepared to fight... but it has not been happening as fast as it needs to".

Iraq has become increasingly reliant on Iranian-backed Shia militias to take on IS in recent months.

The move has raised fears of worsening sectarian tensions as the militias try to drive the jihadist fighters out of predominantly Sunni areas like Anbar.