MOSCOW (Reuters) - U.N. special envoy on Syria Staffan de Mistura will visit Moscow on Thursday for talks on the situation in Syria, RIA news agency quoted him as saying on Wednesday. De Mistura will meet Russian Foreign Minister Sergei Lavrov and Defence Minister Sergei Shoigu to discuss preparations for a new round of Geneva peace talks on Syria and a proposed congress on Syria in Russia s Black Sea resort of Sochi, RIA reported.  