There is only one zigbee standard for the entire world. Where zigbee differs technically is The “profile” used, but that’s more about the industry. It’s not geographic. There’s zigbee home automation (ZHA), which is what smartthings uses, several zigbee energy profiles, Zigbee hospital care etc.
Where the EU and the US differ with regard to zigbee is in the maximum broadcast power allowed by law. This is not a technical distinction. Amplified devices, which are legal in the US, broadcast at a strength almost twice that allowed by law in the EU. The devices would work in any country, but might be illegal in one.
It is Z wave where frequency varies by geographic region.