Is it possible that there may be internal hemorrhoids that cause bleed during defecation?

Yes: Hemorhhoids can ceratainly cause bleeding during defecation. But many other things cause rectal bleeding, as well. Some are serious (like colorectal/anal cancer) and benefit from early diagnosis. Others, like anal fissure, are not so serious, but benefit from treatment. See your doctor - don't self diagnose!

Yes: That is commonly the cause but other causes should be envaulted so discuss with your doctor.