dunhill, thank you for your reply.
That was a nice catch! But I'm already using the alternate tag as you can see in the first post, I just forgot that I was using already.
Code:
<link rel="alternate" hreflang="en" href="http://www.domain.com/" />
<link rel="alternate" hreflang="fr" href="http://fr.domain.com/" />
<link rel="alternate" hreflang="pt" href="http://pt.domain.com/" />
<link rel="alternate" hreflang="es" href="http://es.domain.com/" />
<link rel="alternate" hreflang="it" href="http://it.domain.com/" />
<link rel="alternate" hreflang="ru" href="http://ru.domain.com/" />