MADRID - Russia is NATO's "most significant and direct threat" while China's "coercive policies" challenge NATO's "interests, security and values," according to the alliance's new security doctrine.
The document says NATO no longer views Russia as a strategic partner but stresses the alliance "does not seek confrontation and poses no threat" to the country.
Meanwhile China uses a "broad range of political, economic and military" activities to project power, the doctrine said, outlining the alliance's view of the country for the first time.
NATO leaders signed off the alliance's Strategic Concept, a policy blueprint outlining the organization's aims and tasks for the next 10 years, last formulated in 2010.
The leaders agreed to ramp up reinforcements in Eastern Europe in view of the Russian invasion of Ukraine.
The alliance plans to increase the number of rapid response forces available to NATO from around 40,000 troops to more than 300,000 soldiers.
The NATO Response Force (NRF) are usually under national command, but can be requested for deployment to another ally by NATO's Supreme Allied Commander Europe (SACEUR).
The Baltics, especially Estonia, have pushed NATO hard to shift tactics in light of the Russian invasion of Ukraine and move to fully-fledged defense of alliance territory in Eastern Europe,
replacing a model to relinquish and later recapture lost ground.
NATO leaders also addressed climate change for the first time, describing the challenge as a "threat multiplier... with a profound impact on Allied security," in a joint statement.
In the same statement, NATO leaders agreed to step up support to Ukraine with long-term support including more equipment, supplies, training and help to transition away from Soviet-era military equipment.
Earlier on Wednesday, US President Joe Biden said the United States military presence in Europe is set for a long-term expansion, speaking alongside NATO Secretary General Jens Stoltenberg.
The US president outlined plans for increased US troop deployments in the Baltics, the deployment of two squadrons of US F35 fighters in Britain and additional air defenses in Italy and Germany.