In a large saucepan cook onion and garlic in hot oil until onion is tender but not brown. Stir in water, broth and tomato paste. Bring to a boil; add potatoes and carrots. Simmer 5 minutes. Meanwhile combine egg, cilantro or parsley, salt, oregano and pepper. Add ground beef and rice and mix well. Form into 1-inch meatballs. Add, a few at a time, to the simmering soup. When all meatballs are added, bring soup back to boiling. Reduce heat and simmer about 30 minutes, or until meatballs and vegetables are done.