Maybe Central America, but what's "CFS"?

I'm pretty sure it's NOT Consejo Federal de Seguridad, which was a Peronist secret police force in 1940s Argentina. These fellows don't look like police, and I guess the date is around 1910.

Look very much like Mexican infantry of the late Porfirio Diaz, early Huerta period (say 1910-13). Equipment and uniforms closely match the white and off-white fatigue/summer clothing worn as active service dress by the ill fated Federal Army. They sometimes wore white covers over their kepis (an American observer at Ciudad Juarez commented that keeping the covers clean would be a useful means of keeping soldiers in barracks occupied). However the Federales wore branch insignia (crossed canons etc) or regimental numbers on their kepis and the CFS is a mystery. Could they be provincial troops of some kind? Diaz maintained National Guard units in each of the 27 states as a (largely on paper) reserve for the standing army.

Nice picture though - and those boots are well polished!