Are you aware of the annual World Watch List? This report by Brother Andrew’s ministry, Open Doors, is the most comprehensive available about persecution of Christians. If you want to be informed in your prayers for our suffering brothers and sisters in Christ (and you should want to be), then I recommend this resource to you.
Their website also offers extensive information about each country. North Korea is #1 on the list, so I’ve included the link for their more detailed background and prayer requests about this country.