Pro-Russian separatists in eastern Ukraine’s breakaway regions ordered civilians to be evacuated to Russia on Friday, accusing Ukraine of planning a large military offensive against the two self-proclaimed republics.

Over the last two days, the restive eastern part of the country has seen the worst shelling in years. Ukrainian Defense Minister Oleksii Reznikov stated on Friday that shelling of Ukrainian territory from separatist-controlled areas had increased dramatically in the previous day.

Each side accuses the other of shelling civilian areas heavily. According to Ukrainian authorities, there were 60 violations of the ceasefire on Thursday, many of which involved heavy weapons.

The Ukrainian government denies any plans for an offensive in the east and accuses the separatists of launching a “disinformation campaign.” The evacuations were being organized by authorities in the breakaway republics of Donetsk and Luhansk. The most senior official in the pro-Russian breakaway Luhansk People’s Republic, Leonid Pasechnik, urged men to take up arms.

“The Russian Federation is ready to organize the reception and accommodation of residents of the Luhansk People’s Republic on its territory,” Pasechnik said. “Once again, I appeal to all men capable of wielding weapons to defend their land.”

Both the Ukrainian government and Western officials have warned of the possibility of provocative actions by Russia and the separatist leadership in order to create a pretext for a Russian offensive into Ukraine.

“We are in the most dangerous phase,” a Western official said Friday to reporters. “They were free to leave at any time. Russia could take action within days. Everything we’re seeing makes us even more concerned.”

According to the official, there are 110 Russian battalion tactical groups – a fighting formation of about 1,000 troops – in Ukraine. Russia also has “ready-to-go air power,” according to the official.

On Thursday, US Vice President Joe Biden accused Russia of engaging in a “false flag operation,” shortly after shelling resumed between Ukrainian authorities and separatists in the eastern Ukrainian region of Donbas. Biden has stated that Russia may invade Ukraine “within the next few days.”

Both the Ukrainian government and Western officials have warned of the possibility of provocative actions by Russia and the separatist leadership in order to create a pretext for a Russian offensive into Ukraine.

Since 2014, the Donbas region has seen fighting between Ukrainian forces and separatist fighters. The Ukrainian government in Kyiv claims that the Donetsk People’s Republic and the Luhansk People’s Republic are effectively occupied by Russia. No government, including Russia, recognizes the self-proclaimed republics. The Ukrainian government refuses to engage in direct negotiations with either separatist republic.

In recent years, Russian President Vladimir Putin has distributed approximately 600,000 Russian passports to residents of breakaway regions, a move that observers have argued could pave the way for a Russian intervention in Ukraine.

Since 2014, more than 14,000 people have died in the Donbas conflict. Ukraine claims that 1.5 million people have been forced to flee their homes, with the majority remaining in areas of Donbas under Ukrainian control and about 200,000 resettling in the greater Kyiv region.

An invasion of Ukraine by Russia would be “catastrophic,” UN Secretary General António Guterres said Friday during his opening remarks at the Munich Security Conference in Germany, urging diplomatic efforts to continue.

“I am deeply concerned about the increased tensions and speculation in Europe about a military conflict. I still believe it will not happen, but if it does, the consequences will be disastrous “According to Guterres.

From the Munich conference, US Vice President Kamala Harris warned that “aggressive action” by Russia would be met with “severe consequences” in the form of economic sanctions.

According to a senior US official with direct knowledge and another source directly familiar with the intelligence, the latest US intelligence assessment indicates that Russia is continuing its preparations to invade Ukraine.

According to the senior official’s assessment, which he described as “bleak,” Russia may launch an attack in the coming days.

However, US officials warn that they do not know if Putin has made a final decision to invade and that he may delay or cancel the invasion. Earlier forecasts of Russian military action this week did not come true.