Officials concerned Russia may strike supply line to Ukraine
There have been monumental efforts, especially by Poland, to get weapons into Ukraine and to the front lines.
But a senior official told ABC News there are indications Russia may attack one of those supply chains in Poland before it gets to Ukraine, potentially using air power.
Russian forces have created heavily fortified areas from which to launch long-range artillery, the official said, meaning they can shell cities from a distance rather than send troops into them. Ukrainian President Volodymyr Zelenskyy has repeatedly requested air power assistance in order to destroy these fortified areas.
Ukrainians have seen success in attacking Russian resupply areas, mostly in the north but also among smaller, moving groups.
-ABC News' Martha Raddatz