Some 250 parliamentarians from 28 NATO-member countries and partners gathered Saturday downtown Tirana under high security measures from the local authorities, involving about 600 police and security forces.

Assembly President Michael R. Turner said Russia's aggressive attitude, terrorism and mass migration would be debated at length during the session.

The Assembly is expected to endorse a declaration urging alliance leaders to strengthen collective defense and deterrence, develop a comprehensive strategy for promoting stability in North Africa and the Middle East, ensure that all allies meet military spending targets and boost cooperation with the European Union, according to a draft seen by The Associated Press.