This is what those units were waiting for:
Satellite images show large convoy of Russian forces moving toward Kyiv
Maxar satellite imagery was collected at 10.56am this morning, showing a large deployment of Russian ground forces, containing hundreds of military vehicles, heading northeast of the Ukrainian city of Ivankiv and moving in the direction of Kyiv—approximately 40 miles away.
The convoy extended for more than 3.25 miles and contained fuel, logistics and armoured vehicles such as tanks, infantry fighting vehicles, self-propelled artillery.
Meanwhile, Kiev's mayor just reported the city is completely surrounded (i.e. no reinforcements possible)