TBILISI (Reuters) – Ethnic Armenians in the disputed enclave of Nagorno-Karabakh are preparing for a “long-term blockade” by Azerbaijan, a top separatist official said on Friday, after nearly two weeks without fresh supplies of food and medicine. Azerbaijani civilians identifying themselves as environmental activists have been facing off since Dec. 12 with Russian peacekeepers on the Lachin corridor, the only road across Azerbaijan that links Armenia to Nagorno-Karabakh. The United States and the European Union have urged Azerbaijan to unblock the corridor, warning of severe humanitarian conse…