the BBC has spoken to an expert who says there are two significant challenges facing Ukraine's army in the coming days, despite its forces doing well to slow Russian advances.
Nick Reynolds, research analyst in land warfare at the RUSI think tank, says Ukraine must prevent both scenarios - while continuing to defend the country's cities from Russian attack.
Firstly, there is a risk of Russian troops moving up from the south and making contact with their compatriot forces from the north.
If the two fronts combine into one it would isolate the large number of Ukrainian troops stationed along the line of conflict in Donetsk and Luhansk - where they have been concentrated since 2014.
"Right now Russian progress from the south is slow. But a major reason for those operations is so they can cut off the JFO [Joint Forces Operation area in eastern Ukraine]. It would isolate a significant proportion of the Ukrainian army".
Secondly, Reynolds says Ukraine's military could also be close to exhausting its munition supplies.
"Stocks by their own estimate at the start of the war were to last ten days of fighting. They'll likely be running short fairly soon."
It's difficult to predict what supplies are left seven days in, but given the intensity of the fighting Reynolds predicts Ukraine will not be able to last much longer without fresh air-defence ammunition and artillery shell supplies.
Military aid being transported into Ukraine is having to travel by land after crossing into the country, meaning a slow journey over long distances.
"At the point where Ukrainian forces can't get those types of munitions, they will be at a severe disadvantage even more so than they are now," Reynolds says.
the BBC has spoken to an expert who says there are two significant challenges facing Ukraine's army in the coming days, despite its forces doing well to slow Russian advances.
Nick Reynolds, research analyst in land warfare at the RUSI think tank, says Ukraine must prevent both scenarios - while continuing to defend the country's cities from Russian attack.
Firstly, there is a risk of Russian troops moving up from the south and making contact with their compatriot forces from the north.
If the two fronts combine into one it would isolate the large number of Ukrainian troops stationed along the line of conflict in Donetsk and Luhansk - where they have been concentrated since 2014.
"Right now Russian progress from the south is slow. But a major reason for those operations is so they can cut off the JFO [Joint Forces Operation area in eastern Ukraine]. It would isolate a significant proportion of the Ukrainian army".
Secondly, Reynolds says Ukraine's military could also be close to exhausting its munition supplies.
"Stocks by their own estimate at the start of the war were to last ten days of fighting. They'll likely be running short fairly soon."
It's difficult to predict what supplies are left seven days in, but given the intensity of the fighting Reynolds predicts Ukraine will not be able to last much longer without fresh air-defence ammunition and artillery shell supplies.
Military aid being transported into Ukraine is having to travel by land after crossing into the country, meaning a slow journey over long distances.
"At the point where Ukrainian forces can't get those types of munitions, they will be at a severe disadvantage even more so than they are now," Reynolds says.
有强度的野战不能指望。还好俄军进军速度比1941年古德里安和克莱斯特两个装甲集群包围基辅的速度慢，现在乌克兰的东部部队还有空隙撤退，如果判定被围以后的后果严重，那就应该不惜代价救一部分部队出来。
就凭一辆坦克等着加油的视频，就编造俄军缺油。 如果士兵到了中午等着开饭，是不是就是缺粮食?
这个拜登要好好想想， 当然就算是乌军主力完了， 这个仗在乌西还是可以继续打下去的。只要有足够的军援。
我觉的美欧有点呆， 毛子要真要扔蛋， 还怕找不到理由？ 他现在根本不把世界各国放在眼里， 他可以说“ 你再敢援乌， 我就扔蛋” 你怎么办？ 停下来不援了？
自己用油也不要钱
俄军也没能真正包围乌军重兵集团。