(Reuters) -Russian oil giant Rosneft is not scheduled to export any diesel from the Baltic port of Primorsk in May as demand from Europe was set to decline amid tightening sanctions on Moscow, traders said on Friday. Exports of Russian diesel from Primorsk, a key supply source for Europe, are set to drop by over 30% in May from a month earlier to 1.114 million tonnes, data from traders showed on Friday. Kremlin-controlled Rosneft has been one of the largest exporters of diesel from Primorsk, but the company had so far not planned to load any vessels in May, according to the data. Trading sourc…