Talking to press, Rasmussen restrained Pakistan to open NATO supplies 'immediately'.

The Secretary General and the US president Barack Obama discussed the summit agenda ahead of the 20-21 May high-level meeting which will be NATO’s largest summit, gathering representatives from around 60 nations and organisations.

India, China and Russia have also not been invited to the summit, which will be attended by Qatar, Morocco, United Arab Emirates and Jordan.

The summit, which is being held in the US state of Illinois, will be the third time that NATO holds such a gathering in the United States.“The United States is vital to our Alliance,” Mr. Fogh Rasmussen said.

The Chicago Summit will focus on three key priorities: Afghanistan, capabilities and partnerships. "At the summit we'll discuss the next phase in our engagement in Afghanistan, how we can provide security in a time of austerity and how we can further strengthen our partnerships around the world".