Ukrainian President Petro Poroshenko will meet with key NATO allies - including US President Barack Obama and British Prime Minister David Cameron - at a summit in Wales later today.

The NATO summit will see 28 heads of states, along with thousands of delegates and their advisors, discuss how to deal with Russia, and its involvement in the conflict in eastern Ukraine.

World leaders will also have meetings about the growing terrorist threat from Islamic State militants.

British Prime Minister David Cameron says the NATO alliance in vital in maintaining world peace:

As the summit got underway NATO Secretary General Anders Fogh Rasmussen said the meeting would enhance international security and prosperity...