Question about Public vs. External Debt

I am wondering what is the difference between the two. I noticed that for some countries with low public debt (ie. Australia’s public debt is at 16.2%), their “debt external” is extremely high (ie. Australia’s external debt is $ 509.6 billion). What is up with that? Is public debt what the government owes to creditors within the country while external debt is what they owe to creditors outside the country? Another interesting case is that I know that the US National Debt clock is at $8.3 trillion something now (which is the same as their public debt) but their external debt puts them at $8.8 trillion.