It's not likely you can get it repaired under warranty, and probably not at all even if you pay for it. Parts for a USA iPhone may not be available in other regions.
Legal - iOS Warranty Document Us - Apple - "IMPORTANT RESTRICTION FOR iPHONE, iPAD AND APPLE TV SERVICE. Apple may restrict warranty service for iPhone, iPad and Apple TV to the country where Apple or its Authorized Distributors originally sold the device."
The warranty does not outright deny warranty coverage in other countries but there are many limitations to the effect Apple almost may well be unable and/or refuse to do repairs under warranty, or even repairs at all, except in the country of purchase. You may have to negotiate in an Apple Store in person and be willing to reach a compromise with what they have available. If this is not suitable, the device would have to be sent to a friend in the country of purchase to handle any repair claims because Apple will not handle international shipping.
Did you try the check coverage page I provided? That information alone would serve as adequate information for warranty service.
Note that others may post later and tell you Apple will "not" provide warranty service. That is not what Apple says, so they are providing you with inaccurate information. Read what your warranty says and the word "may" (which is likely exactly what I quoted).