A group of experts led by former US Secretary of State Madeleine Albright is due to report on the future strategy it recommends for Nato.
The challenges facing Nato include the war in Afghanistan, relations with Russia and missile defence.
Afghanistan has been a huge strain on the alliance and fuelled tensions on whether its future focus should be on distant missions or closer to home.
Nato is due to agree on a new strategic concept at a summit in November.
The experts will present their report at Nato headquarters in Brussels on Monday morning.
Russian issue
As the alliance has adapted from its Cold War past, it has taken in new members from central and eastern Europe, some with different security perspectives from those of traditional allies like the United States and Britain.
This new report is expected to offer a frank assessment of the difficulties facing Nato in adapting further and deciding whether and how to take on new challenges.
These include terrorism, cyber security, missile defence and how to square a desire for a closer relationship with Russia with the residual suspicions of some new members about Moscow’s ambitions.
The report, Nato officials hope, will help spur a debate leading to agreement on a new strategy at a summit in November.
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