奥巴马主持暴力极端主义会议

Flanked by the leaders of Nigeria and Iraq – two countries on the frontline of the fight against violent Islamic extremism – US president Barack Obama was clear about the size of the challenge:

"There are going to be successes and there are going to be setbacks. This is not a conventional battle. This is a long-term campaign -- not only against this particular network, but against its ideology."

The US led coalition against ISIS has grown to some 60 nations, with President Obama announcing the newest members as Nigeria, Tunisia and Malaysia. He also praised the armed services from the nearly two dozen nations who are now contributing to the military campaign.

But he was clear that it would not be enough just to defeat them on the battlefield. He said ideologies are not defeated by guns but only by better ideas. But Nigerian President Muhammadu Buhari stressed that his country still needed military aid:

"We certainly need to do more. We need to take military action combined with effective border security, intelligence collection and sharing and vigorous policy action. These alone may not suffice but they can certainly stem the tide and reverse the process of recruitment, movement and effective operation of foreign terrorist fighters and their associated radical extremists.'

The Iraqi leader – Haider al-Abadi – sitting next to Obama - also stressed that his country needed support in order to fight the threat on its doorstep.

"We cannot finance all these battles that we are seeking to win. We need your help, and the help of the international community in financing and the equipment of our soldiers. We need your support also to take care of the people who lost their loved ones."

The meeting of more than 100 world leaders lasted several hours but what concrete difference it will make is unclear. Tomorrow Russia – who was not invited – will host a special UN Security Council meeting on the same issue –highlighting not just the huge challenge the world faces in defeating the threat of violent extremism but also the sharp differences which exist in how to tackle it.

For CRI, I'm Kate Fisher at the United Nations in New York.