mod_geoip can be a wonderful thing.
Code:
<IfModule mod_geoip.c>
GeoIPEnable On
GeoIPDBFile /usr/share/GeoIP/GeoIP.dat
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^RU$
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^TW$
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^CN$
RewriteRule ^(.*)$ [F]
</IfModule>
</IfModule>