Recent actions by Russia constitute the most serious escalation of the conflict since Moscow invaded Ukraine in February, NATO Secretary-General Jens Stoltenberg said on Friday.
"This is the largest attempted annexation of European territory by force since World War II," Stoltenberg said.
"Putin has mobilised hundreds of thousands of more troops, engaged in irresponsible nuclear sabre rattling and now illegally annexed more Ukrainian territory. Together, this represents the most serious escalation since the start of the war," Stoltenberg told a news conference.
Stoltenberg also reiterated that NATO must continue supporting Ukraine because it will make the world even more dangerous if the country fails to exist as an independent state.
Otherwise, Putin or other authoritarian powers "will see that with impunity one can use military force and invade its neighbor," he said.
Referring to the recent announcement by Ukrainian President Volodymyr Zelenskyy on applying for NATO membership under accelerated procedure, Stoltenberg said the country, as any sovereign nation, has the right to "choose its own path" and decide which alliance it adheres to.
At the same time, he underlined, it is up to the NATO allies to decide by unanimity on Ukraine's membership.
Asked about the suspected sabotage of the Nord Stream pipelines, Stoltenberg confirmed that NATO ships and planes are present in the Baltic Sea and the North Sea to demonstrate the alliance's readiness.
In addition, the "ships are also collecting information data which can be helpful both for the ongoing investigation, and also to monitor these critical energy infrastructures," he said.
NATO allies also step up "sharing of intelligence and sharing of information" to help the investigation and to prevent further incidents, he said.
"This is the largest attempted annexation of European territory by force since World War II," Stoltenberg said in a press conference on Friday.
