Is it permissible to collect Zakat al-Fitr from one country and send it to another poor country whose people are in dire need?

The Sunnah is to distribute Zakat al-Fitr to the poor of the country from which it was extracted. If there are no poor people there, or if there are those in greater need elsewhere, then there is no harm in sending it to the people of a country who are in greater need of it.