Return results from two countrys in Adwords API

Hi E's, For get relation keywords I use Adwords API.
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# Create seed keyword structure.
$seed_keyword =
  '<negative>false</negative>' .
  '<text>'.$wordforapi.'</text>' .
  '<type>Exact</type>';
$use_synonyms = '<useSynonyms>true</useSynonyms>';

# Get keyword variations.
$request_xml =
  '<getKeywordVariations>' .
  '<seedKeywords>' . $seed_keyword . '</seedKeywords>' .
  $use_synonyms .
  '<languages>pt</languages>' .
  '<countries>PT</countries>' .
  '</getKeywordVariations>';
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In line of code you can see above, I tell to the API, I want relation keywords of word "europe", from Portuguese language and from Portugal country.
I want extend the result for two country's at the same time. I don't know if adwords api accept this.

So, if I want extend the country to Portugal and Brazil at the same time what I put between <countries>....</countries>.
I try to put PT-BR and PT, BR, and the system return this error: This country code is not valid.  PT-BR.
Maybe what I want is not possible, but I have to make sure.

Regards, JC