Obama admits US lacks 'complete strategy' against IS

The United States still lacks a "complete strategy" for training Iraqi forces to fight the Islamic State (IS) group, US President Barack Obama has said,

Acknowledging military setbacks, Obama said the Pentagon was reviewing ways to help Iraq train and equip its forces.

His comments come a day after British Prime Minister David Cameron said that the UK would send 125 new military advisers to Iraq to train local forces.

Cameron's announcement was made during a meeting of G7 leaders in Germany, where the campaign against the IS was one of several security issues on the agenda.

Iraqi Prime Minister Haider al-Abadi was also invited to join the leaders for talks on the security situation in the Middle East and met one-on-one with Obama shortly before the president departed for Washington.

Obama indicated that simply increasing the number of Americans in Iraq would not resolve the country's issues.

The US currently has about 3,000 troops there for train-and-assist missions.

"We've got more training capacity than we have recruits," he said at the close of the two-day meeting.

He urged Abadi and his Shia-led government to allow more Sunnis to fight the Islamic State.

The White House has long blamed Iraq's sectarian divisions for stoking the kind of instability that allowed the militants to thrive.

But some Republicans in the US say the Islamic State's strength is a result of what they see as Obama's muddled and ineffective strategy.

The US leader was sharply criticised in August last year for saying the US did not have an overall strategy for fighting the Islamic State - a statement that was reiterated yet again on Monday.

Despite US-led coalition airstrikes, IS has continued to make gains in Iraq.

In May the militants seized Ramadi, the capital of Anbar, Iraq's largest province.

A year on since IS launched its offensive, Iraq is still struggling to survive as a unified nation, gripped by seemingly endless violence, sectarianism and humanitarian tragedy.