Moscow, 21 February 2022 (dpa/MIA) - Separatists in the east of Ukraine turned up the heat on Monday as a string of events seemed to be setting the stage for a Russian invasion of its neighbour and former Soviet republic. In the self-proclaimed Donetsk People's Republic, separatist leader Denis Pushilin called all men to arms to fight against Ukrainian government troops. Ukraine has repeatedly stressed that it is not planning an offensive against the pro-Russian separatists. Pushilin spoke of massive shelling from the Ukrainian side. Two schools, a hospital and a transformer station were hit, the Donetsk authorities said. From the regions controlled by separatists loyal to Moscow, mainly women and children continued to be brought to Russia in buses and trains. More than 61,000 people have followed the suggestion to flee to Russia, the Interfax news agency reported, and tens of thousands have arrived in emergency shelters in various parts of Russia. The men had to stay in the disputed areas. "I call on the male population, all those who can hold a gun, to join the district military commands and stand up for the protection of their families, children, wives, mothers and for our fatherland," Pushilin said. In a call for help to Russian President Vladimir Putin, the two self-proclaimed people's republics of Luhansk and Donetsk demanded recognition as independent states. Donetsk's Pushilin called on Putin to conclude a treaty of friendship and military assistance with the "people's republic." This would allow Russia to station thousands of soldiers there, as in the regions of South Ossetia and Abkhazia that broke away from Georgia. After a war in Georgia, Russia recognized the regions as independent states in 2008. In Luhansk, the leader there, Leonid Pasechnik, addressed Putin via Russian state television: "Dear Vladimir Vladimirovich, in order not to allow mass deaths of the people of the republic ... I ask you to recognize the sovereignty and independence of the Luhansk People's Republic." The Russian parliament had also passed a resolution to Putin last week asking for recognition of the "people's republics." Putin had left a decision open but had convened a meeting of the National Security Council on Monday where the issue was to be discussed. The meeting was being held as reports of attacks on Russian soil emerged. The NATO military alliance says Moscow could use an alleged Ukrainian attack on Russia as a pretext for an invasion. The FSB, the domestic intelligence service responsible for Russia's border protection, said that one of its posts in the Rostov region has been fired upon and destroyed. The FSB issued pictures to support the claim. Russian authorities had also previously reported such strikes from the Ukrainian side. The FSB also claimed that a group of Ukrainian saboteurs had entered Russian territory and had been "destroyed." Five people were killed, but there were no injuries on the Russian side. The separatists have been blaming a group of Ukrainian agents for attacks in the conflict area for days. Russian-backed separatists said on Monday that two people - including one of their fighters - are dead following gunfire from Ukrainian army forces. The other deceased was a miner who was shot on his way to work, the rebel forces posted on Telegram. Diplomatic efforts were continuing to avert a Russian invasion. The Kremlin said it was open in principle to a summit between Putin and US President Joe Biden, who had already agreed "in principle" to a meeting, according to the White House. Russian Foreign Minister Sergei Lavrov said he plans to meet his US counterpart, Antony Blinken, on Thursday in Geneva. But Washington has not toned down its warnings of an imminent invasion of Ukraine. "We have seen just in the last 24 hours, further moves of Russian units to the border with no other good explanation other than they're getting into position to attack we couldn't predict the exact time or day, but it certainly looks like the Russians are proceeding," Biden's National Security Advisor Jake Sullivan said on Monday. "It will be a war waged by Russia, on the Ukrainian people, to repress them, to crush them, to harm them," Sullivan said. The European Union needs to impose immediate sanctions on Moscow to show it is "walking the walk" instead of waiting for a feared Russian invasion, Ukraine's Foreign Minister said. More than 14,000 people have died in periodic fighting since the conflict erupted in 2014 following Russia's annexation of the Ukrainian peninsula of Crimea, with a peace deal put in place in 2015 largely ignored. The information provided by the FSB could not be independently verified, nor can the state of hostilities in the region.