This video describes how to use block/control access from certain countries to your application:
1) CloudFront Geo Restrictions - https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/georestrictions.html
2) CloudFront Functions - https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/example-function-redirect-url.html
3) AWS WAF - https://docs.aws.amazon.com/waf/latest/developerguide/waf-rule-statement-type-geo-match.html