Since it is hard for young children to understand someone else's point of view, there will be some arguments. Young children react to the moment and may do things without thinking.
Aggressive behavior is often not meant to be hostile or to hurt others. In fact, young children frequently get upset when another child gets hurt while playing.
When something happens that is upsetting, talk with everyone. Help each child try to see the other child's point of view. This way, children will learn how to avoid and deal with arguments.
If you are concerned about your child's aggressive behavior, talk to your pediatrician.