NATO, the largest and most powerful military alliance, has branded Russia the biggest threat to Western security after its invasion of Ukraine.
World leaders have been meeting in Spain, with conversations centred around the Kremlin's invasion and Beijing's growing international ambitions.
As part of the two-day summit, a new strategic concept was put forward that sets the alliance's areas of focus and is updated roughly once a decade.
NATO has agreed to modernise Kyiv's beleaguered armed forces, saying it stood fully behind Ukrainians' heroic defence of their country. US President Joe Biden announced more land, sea and air force deployments across Europe from Spain to Romania and Poland bordering Ukraine.
Britain said that it would provide another 1 billion pounds $1.7 billion of military support, including air defence systems, uncrewed aerial vehicles and new electronic warfare equipment.
In a nod to the deterioration of relations with Russia since the invasion, a NATO communique has labelled Russia the most significant and direct threat to the allies' security As world leaders met, Russian President Vladimir Putin warned Finland and Sweden that if they welcome NATO troops and military infrastructure onto their territory, Russia would respond in kind.
Two formerly non-aligned Baltic countries were invited Wednesday to join the Western military alliance.
Putin said that Russia will have to create the same threats for the territory from which threats against us are created. For the first time, Beijing was mentioned in NATO's strategic concept, which sets the alliance's areas of focus.
It said China's stated ambitions and coercive policies challenge our interests, security and values and accused the nation of using malicious hybrid and cyber operations, confrontational rhetoric and disinformation to target NATO allies and harm NATO's security.
The document also touches upon China's economic ambitions, stating that Beijing was trying to control key technological and industrial sectors, critical infrastructure, strategic materials and supply chains.
China is not our adversary, but we must be clear-eyed about the serious challenges it represents.