“Ukraine will continue to follow only the diplomatic path in the interest of a peaceful settlement.”

There was no immediate response from the Kremlin.

To see: Kamala Harris warns Russia of unprecedented sanctions if it invades Ukraine further

Zelensky spoke hours after pro-Russian separatist leaders in eastern Ukraine ordered a full military mobilization on Saturday, while Western leaders issued increasingly serious warnings of a Russian invasion of his neighbor seemed imminent.

In fresh signs of fear that a war could start in days, Germany and Austria have told their citizens to leave Ukraine. German air carrier Lufthansa LHA,
-1.80%

DLAKY,
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canceled flights to the capital, Kyiv, and to Odessa, a Black Sea port that could be a key target during an invasion.

The NATO Liaison Office in Kyiv announced that it was transferring staff to Brussels and the city of Lviv in western Ukraine. Meanwhile, senior Ukrainian military officials have come under bombardment while touring the frontline of the nearly eight-year-old separatist conflict in eastern Ukraine.

To see: US closes Kyiv embassy and relocates operations to western Ukraine, Blinken says

Officials fled to a bomb shelter before leaving the area, according to an Associated Press reporter who was on tour.

Violence in eastern Ukraine has increased in recent days as Ukraine and the two pro-Russian rebel-held regions have accused the other side of escalating. Russia said on Saturday that at least two shells fired from a government-held part of eastern Ukraine had landed across the border, but Ukrainian Foreign Minister Dmytro Kuleba said dismissed this claim as “a misrepresentation”.

Sporadic violence has erupted for years along the line separating Ukrainian forces from Russian-backed rebels, but the recent spike in shelling and shelling could spark a full-scale war.

The United States and many European countries have been claiming for months that Russia, which has moved about 150,000 troops near the Ukrainian border, is trying to create pretexts to invade.

Don’t miss: Russia mapped ‘false flag’ incident in eastern Ukraine as pretext to invade, says ‘highly credible’ US intelligence assessment

Also see: Russia has a plan for a doctored video that would provide a pretext for the invasion of Ukraine (reports)

“They are unfolding and are now ready to strike,” US Secretary of Defense Lloyd Austin said during a visit to Lithuania on Saturday.

Harris opened his meeting with Zelensky by saying the world was at “a watershed moment in history.”

Earlier on Saturday, Denis Pushilin, the head of the pro-Russian separatist government in Ukraine’s Donetsk region, cited an “immediate threat of aggression” from Ukrainian forces in his announcement. Ukrainian officials have vehemently denied plans to take rebel-held areas by force.

“I appeal to all men in the republic who can hold arms to defend their families, their children, their wives, their mothers,” Pushilin said. “Together we will achieve the coveted victory we all need.”

A similar statement followed from his counterpart from the Luhansk region. On Friday, the rebels said they had begun evacuating civilians to Russia with an announcement that appeared to be part of an effort, backed by Moscow, to portray Ukraine as the aggressor.

German Foreign Minister Annalena Baerbock said the evacuation orders could be a tactic to trigger a wider attack. “To put it very clearly, Ukraine gave no reason for the evacuation that was ordered yesterday,” she said. “These are the facts on the ground. We must not allow so-called reasons for war to be constructed out of hot air.

US President Joe Biden said Friday evening that, based on the latest US intelligence, he had become “convinced” that Russian President Vladimir Putin had decided to invade Ukraine and attack the capital.

“From that point on, I’m confident he made the decision,” Biden said. “We have reason to believe that.”

Biden reiterated that an assault could happen in the “coming days.”

Meanwhile, Russia conducted massive nuclear exercises on Saturday. The Kremlin said Putin, who has pledged to protect Russia’s national interests against what he sees as encroaching Western threats, was watching the drills with Belarusian President Alexander Lukashenko from the Situation Room. Notably, the planned exercise involves the Black Sea Fleet based in Crimea.

Russia annexed the Crimean peninsula after seizing it from Ukraine in 2014.

Extract from the archives (March 2014): Putin: Russians are ‘still cornered’

Underlining Western concerns over an imminent invasion, a US defense official said about 40-50% of Russian ground forces deployed near the Ukrainian border have moved to closer attack positions of the border.

The change has been in the works for about a week, other officials said, and does not necessarily mean Putin has decided to start an invasion. The defense official spoke on condition of anonymity to discuss internal U.S. military assessments.

The official also said the number of Russian ground units known as battalion tactical groups in the border area had risen to 125 from 83 two weeks ago. Each group has 750 to 1,000 soldiers.

Lines of communication between Moscow and the West remain open, with US and Russian defense chiefs speaking on Friday. French President Emmanuel Macron scheduled a phone call with Putin on Sunday. US Secretary of State Antony Blinken and Russian Foreign Minister Sergei Lavrov have agreed to meet next week.

Immediate concerns centered on eastern Ukraine, where Ukrainian forces have been fighting pro-Russian rebels since 2014 in a conflict that has claimed some 14,000 lives. Violations of a 2015 ceasefire agreement, including shelling and firing along the line of contact, are common.

A car bomb exploded in the center of the rebel-held city of Donetsk on Friday.

Adding to the tension, two explosions rocked the rebel-held city of Luhansk on Saturday morning. No injuries were reported in the incidents.

The Ukrainian army said two of its soldiers died on Saturday following rebel-side fire.

On Saturday morning, separatists in the Luhansk and Donetsk regions, which form Ukraine’s industrial heartland known as Donbas, said thousands of residents of rebel-held areas had been evacuated to Russia.

Russia said it issued around 700,000 passports to residents of the rebel-held regions of eastern Ukraine. Claims that Russian citizens are in danger could be used to justify military action.

Pushilin, head of the Donetsk rebel government, claimed in a video statement that Ukraine would order an imminent offensive in the region.

Metadata from two videos released by the separatists announcing the evacuation show the files were created two days earlier, the AP confirmed. Some anti-Moscow observers said the purported evacuation buses seen in video footage appeared to be half-empty, at best.

US authorities have alleged that the Kremlin’s efforts to come up with a pretext for the invasion could include staged and pre-recorded videos.

Authorities in Russia’s Rostov region, which borders eastern Ukraine, have declared a state of emergency, claiming an influx of evacuees. Media on Saturday described chaos in some of the camps assigned to house people from eastern Ukraine. Reports said there were queues of buses and hundreds of people waiting in the cold for hours to be housed without access to food or toilets.

Putin ordered the Russian government to offer 10,000 rubles (about $130) to each evacuee, an amount equivalent to about half of an average monthly salary in eastern Ukraine.