Cameron doesn't rule out military intervention in Iraq

London: British Prime Minister David Cameron Thursday said he does not rule out joining the air strikes the US was carrying out in Iraq against the strongholds of the Islamic State group, but said it was not a current priority.

Cameron told reporters during the North Atlantic Treaty Organisation (NATO) summit that his main strategy was helping groups fighting on the ground like the Peshmerga Kurdish forces.

"I certainly don't rule anything out. We should pursue our national interests," he said.

Cameron said the Western powers should not do things unilataterally without considering the eventual effects of those more closely involved.

"The most important thing to consider is that we mustn't see this as something where you have a Western intervention over the heads of neighbouring states and leaving others to pick up the pieces."

He said the first thing to do was help those who were currently fighting on the ground and disclosed that the British government was discussing the possibility of arming the Kurdish forces.

The British prime minister also said his country can help in advising Kurdish militias.

Earlier in the day, Western leaders criticised Russia for its "destabilising" influence on the crisis in Ukraine.

NATO and Britain warned that pressure on Russia would be raised if it did not change course in eastern Ukraine.

Some 2,600 people have died in fighting between Ukrainian troops and pro-Russian rebels.

Cameron chaired an emergency session of the Cobra committee Wednesday to discuss the threat by Islamic State militants.

Cobra stands for Cabinet Office Briefing Room A and it meets to discuss high-priority issues that cross departmental borders within government. It plans government responses in times of emergency.

The British government has confirmed that Islamic State was holding a Briton hostage, who has been identified in the international media as David Haines.

Cameron is the host of the two-day NATO summit which began Thursday. Under discussion by the alliance are Ukraine, Iraq and the scheduled departure of the NATO-led international forces from Afghanistan by the end of the year.