From the article:
The tank divisions formed the hard hitting core of the mechanised corps. They were armed with a mix of tanks with the best armed based around the new T-34 tank. The new T-34 tanks were issued to a number of tank divisions in the mechanised corps, and the Germans began to run into them within the first few days of the invasion. The T-34 caused the Germans to often avoid direct engagement with this well-armoured tank and powerful 76mm gun.