The eastern Ukrainian city of Bakhmut endured heavy artillery fire on Monday in what the NATO chief said appeared to be the start of a major new Russian offensive as the first anniversary of the war neared. Ukrainian defenders, who have already held out there for months, were braced for new ground attacks, Ukrainian military officials said. Positions in Bakhmut have been fortified and only people with a military role were being allowed in, a deputy battalion commander said. Any civilians who still wanted to leave the city would have to brave the incoming fire, he said. Bakhmut is a prime objective for Russian President Vladimir Putin and its capture would give Russia a new foothold in the Donetsk region and a rare victory after several months of setbacks. Donetsk and Luhansk regions make up the Donbas, Ukraine's industrial heartland now partially occupied by Russia which wants full control. "... The reality is we have seen the start (of a Russian offensive) already because we see now what Russia does now - President Putin does now - is to send thousands and thousands more troops, accepting a very high rate of casualty," NATO Secretary-General Jens Stoltenberg told reporters in Brussels. The Russian assault on Bakhmut has been spearheaded by mercenaries of the Wagner group, who have made small but steady gains. The renewed Russian bombardments made the situation there even more acute. "The city, the city's suburbs, the entire perimeter, and essentially the entire Bakhmut direction and Kostyantynivka are under crazy, chaotic shelling," said Volodymyr Nazarenko, deputy commander of Ukraine's Svoboda battalion. Nazarenko said that although no fighting was taking place in the city center right now, the defenders were prepared to meet any assault. "The city is a fortress, every position and every street there, almost every building, is a fortress," he said. The Russian defense ministry said its troops had pushed forward a few kilometers along the frontlines, without specifying exactly where. The Ukrainian military reported Russian shelling all along the frontline and said 16 settlements had been bombarded near Bakhmut. It said that over the past day, its forces had repelled a number of attacks near Bakhmut as well as assaults in Kharkiv, Luhansk and Zaporizhzhia regions. Luhansk Governor Serhiy Haidai said Russian forces had attacked Bilogorivka from all sides before dawn on Monday. Regarding the Russian offensive, he said: "Preparations for this offensive are already under way, the amount of shelling, air strikes and attacks by small groups has already increased. We are waiting for them to start massive round-the-clock attacks." Reuters was not able to independently verify the battlefield reports. Village under fire The frontline village of Chasiv Yar has been shelled heavily in recent days as Russian troops work to cut off routes to Bakhmut city. One family told Reuters they had decided to leave the village after a projectile landed in their yard, damaging the roof and windows of their home. Grandmother Raiisa Akusova, 75, suffered a heart attack shortly after setting off for the evacuation center in Dnipro and died, they said. The United Nations' human rights office said on Monday that it had recorded 7,199 civilian deaths and 11,756 injured since the Feb. 24 invasion, mostly from shelling and missile and air strikes. However, it believed the actual figure was far higher. With Ukraine desperate for more weapons and munitions to turn the tide of the war, defense ministers from several NATO countries allied to Kyiv will meet in Brussels on Tuesday to discuss possible further military aid. Ukraine says it needs fighter jets and long-range missiles to counter the offensive and recapture lost territory. NATO's Stoltenberg said he expected the issue of aircraft to be discussed at the meeting, but that Ukraine needed urgent support on the ground now. NATO said on Monday it would increase targets for the stockpiling of ammunition as Kyiv is burning through shells much faster than Western countries can produce. A year of war in Ukraine has left allied stocks badly depleted. "The current rate of Ukraine's ammunition expenditure is many times higher than our current rate of production," Stoltenberg told reporters. A European diplomat told Reuters: "If Europe were to fight Russia, some countries would run out of ammunition in days." Russia invaded Ukraine last Feb. 24 saying its neighbor posed a security threat. Kyiv and the West say the action was nothing more than a land grab. Putin's forces failed in an early bid to capture the capital and the conflict has since become a war of attrition that has killed thousands of soldiers and civilians and left whole cities in ruins.