It's important to understand that an Apple AIrTag does NOT know its location. It has no means to do so as it doesn't employ GPS technology. Instead, it relies on the Apple Find My network, which literally consists of millions of iPhones. When any of these are within Bluetooth range of the tag, it will pick up the tag's ID, and along with the phone's GPS location, relay those to the Apple servers over an Internet connection. That is where you would see it with the Find My app on your iPhone.
So, in this instance that iPhone may be yours. The location information you see for your AirTag would be the location of your phone. One reason it may appear as in another country could be if you use a VPN app on your phone.