Minor correction: in re-reading the text I note that the PM said “Slavs” not “Slovenians” (i.e. Sloveni not Slovenci) but even so, his claim is still wrong. Unless he’s making a convoluted observation about Serbs being the largest South Slavic ethnic group.
クロアチア、スロベニアで多国籍軍事演習 The exercise will occur Sept. 9-23, and will include more than 1,900 Soldiers and security forces from Albania, Bosnia and Herzegovina, Croatia, Hungary, Kosovo, Macedonia, Montenegro, Slovenia, the United Kingdom, and the United States.