NATO Secretary-General Jens Stoltenberg told German public broadcaster ARD on Saturday that all signs suggest Russia "is planning a full-scale attack on Ukraine."
"No troops are being withdrawn, as Russia says, but new troops are being added," he said, adding that there were also indications that Russia was preparing to create a pretext for an attack.
Still, Stoltenberg said NATO is committed to a political solution. "We want to get Russia to change course and sit down with us," he said.
NATO has relocated staff from Kyiv to western Ukraine and Brussels amid the escalating tensions, according to a statement shared with DW.
Ukraine is not a member state, and NATO has no troops there, but there are areas of cooperation and some individual NATO member states have made contributions to Ukraine's national defense.
In Kyiv, NATO has maintained a NATO Liaison Office and a NATO Information and Documentation Center since the late 1990s.
Meanwhile, the White House reiterated warnings that Russia could launch an attack against Ukraine at any time, and said that US President Joe Biden would convene a rare meeting of the National Security Council on the situation in Ukraine.