Oscar:
Jonas is correct. (Thank you, Jonas!)
Currently, we do not offer a parameter in either the Streaming or REST APIs that would allow direct targeting of (and filtering by) country. However, as Jonas pointed out, you can request Tweets that have been geotagged (by the user who created them), with the geotag falling within certain parameters.
For the Streaming API (current Tweets, as they happen), check out the [node:5892, hash=“locations”, title=“documentation for the location parameter”] in the [node:10389] endpoint.
For the REST API (past Tweets), check out the documentation for the geocode parameter in the [node:10287] endpoint.
If you use boundaries that are geographically broader than just the country you’re interested in, you can then further filter those results within your own code by checking whether a particular Tweet’s geotag falls within the geographic boundaries of the country (which you will probably have to use a third-party database or library for).
Keep in mind, however, that using the options above will limit the Tweets returned to only those that have been geotagged, so you will miss many Tweets generated within the country of interest (since many users have not enabled geotagging).
I hope that’s helpful!