The war in Afghanistan, a missile shield for Europe and the pooling of military resources in times of austerity top the agenda of the NATO summit in Chicago on Sunday and Monday.

AFGHANISTAN

US President Barack Obama and fellow NATO leaders will fine-tune plans to hand security control to Afghan troops and withdraw 130,000 combat troops from Afghanistan by late 2014.

The 28-nation alliance will also debate post-2014 support, which is expected to focus on continuing to provide training to Afghan security forces.

NATO will debate the size of the Afghan force and the funding it will need after 2014. The military and police force will grow to 352,000 this year but a US proposal foresees a reduction to 228,000.

The future cost to support the Afghan troops is estimated at $4.1 billion per year. The United States is expected to foot half the bill and Washington wants the international community to provide the rest.

MISSILE SHIELD

NATO will declare the start of an "interim capability" of a US-led missile shield to protect Europeans from the threat of ballistic missiles from foes such as Iran.

The announcement will mean that US warships armed with missile interceptors and an early-warning radar system in Turkey will come under command and control of a NATO base in Ramstein, Germany.

The missile defence system is being deployed over several years. Poland and Romania have agreed to host US land-based SM-3 missiles while the US Aegis ships are based in a Spanish port.

Scheduled to become fully operational in 2018, the system has irked Russia, which fears it will undermine its nuclear deterrent and has threatened to deploy weapons to EU borders in response.

To ease Russian concerns, NATO has urged Moscow to cooperate in the system but the two sides have struggled to find a compromise.

SMART DEFENCE

The summit will be the launching pad for NATO's "Smart Defence" initiative, a push to encourage joint military projects in order to make up for dwindling budgets at a time of austerity across the alliance.

Between 20 and 25 projects will be announced in Chicago, ranging from training helicopter pilots to the joint management of munitions.

The United States, which accounts for 75 percent of NATO's military spending, has pressed European allies for years to pull their own weight, but the debt crisis is making it even more difficult for them to invest in new weapons.

The NATO-led air war in Libya last year drove home the transatlantic disparity and the stark realities for Europe's armed forces: a serious shortage of aerial refueling tankers, surveillance drones and precision-guided bombs.

PARTNERSHIPS

NATO wants to strengthen its partnerships around the world, drawing from the success of its cooperation with Qatar, the United Arab Emirates and Jordan in the air campaign in Libya last year.

The leaders of the 22 nations participating in the NATO-led mission in Afghanistan were invited to the summit.

NATO wants to deepen relations with traditional partners such as Australia, Japan, South Korea and New Zealand.

But three military powers not involved in NATO operations, China, India and Israel, were not invited to the summit.

Russian President Vladimir Putin declined to attend.