Russia and China are taking advantage of changes in the "strategic environment" that has prevailed for almost a century to gain influence and undermine American objectives, according to a new strategy document issued by U.S. intelligence agencies.

The document, released Tuesday, says global trends such as the weakening of international institutions, attacks on Western democracy and isolationist tendencies within governments have emerged as major challenges.

"Russian efforts to increase its influence and authority are likely to continue and may conflict with U.S. goals and priorities in multiple regions," according to the strategy paper released by Director of National Intelligence Dan Coats. "Chinese military modernization and continued pursuit of economic and territorial predominance in the Pacific region and beyond remain a concern, though opportunities exist to work with Beijing on issues of mutual concern" including North Korea's nuclear arsenal.