US President Barack Obama says he has authorised air strikes against Islamic militants in northern Iraq but will not send US troops back to the country.

He said Islamic State (IS) fighters would be targeted to prevent the slaughter of religious minorities or if they threaten US interests.

No strikes have been made yet but the US has made humanitarian air drops to Iraqis under threat from the militants.

IS has seized Qaraqosh, Iraq's biggest Christian town, forcing locals to flee.

The Sunni Muslim group, formerly known as Isis, has been gaining ground in northern Iraq since it launched its onslaught in June.

It now controls large swathes of Iraq and Syria and says it has created an Islamic caliphate in its territory.

Speaking at the White House on Thursday evening, Mr Obama said US military aircraft had dropped food and water to members of the Yazidi religious minority community trapped on Mount Sinjar by IS fighters.

Officials had warned that the Yazidis faced starvation and dehydration if they remained on the mountain, and slaughter at the hands of the IS if they fled.

Obama said the US could not turn a "blind eye" to the prospect of violence "on a horrific scale", especially when the Iraqi government had requested assistance.

He said the US would act "carefully and responsibly, to prevent a potential act of genocide".

US air strikes would target IS fighters, should they threaten Baghdad or move towards Irbil, where there is a significant presence of US diplomats and military advisers, Mr Obama said.

In addition, he authorised strikes "if necessary" to help Iraqi government forces break the siege at Mount Sinjar and rescue the trapped civilians.

"The only lasting solution is reconciliation among Iraqi communities and stronger Iraqi security forces," Mr Obama added.

 (BBC)