How to protect aws account.

Hello.

Although this is not a method of restricting to specific countries, it is possible to restrict IAM user usage by IP address.
https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_aws_deny-ip.html

When it comes to protecting AWS accounts, IAM users, etc., I think it would be safe to go through the following documents.
https://repost.aws/knowledge-center/security-best-practices

If you want to restrict the region you want to use, you need to set the policy as described in the document below.
https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_aws_deny-requested-region.html

If you are using AWS Organizations, you can also restrict the regions that can be used with SCP.
https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps_examples_general.html