Get country name with option 'radius'

Greetings!

Is using 'nearbyplace' the only way to use 'radius' option when retrieving country name?

I need to retrieve only the countryname from geonames db.
My problem is that the lat/lon position is not necessarily (never) a place on land, and therefore a radius value is needed.

I understand from the documentation at http://geonames.edesign.no/geonames/docs that none of the country options have implemented 'radius=' (countrycode nor countrysubdivision). However, the documentation at http://geonames.org states that a radius search is possible even on the countrycode/countrysubdivision.

Thanks