Oil rose further above $30 a barrel on Tuesday, lifted by hopes that OPEC and non-OPEC producers may be edging closer to a deal to tackle one of the biggest supply gluts in decades. The Organization of the Petroleum Exporting Countries is making renewed calls for rival producers to cut supply alongside its members, but Russia, seen as key to any deal, has so far refused to cooperate. Iraq’s oil minister said on Tuesday he saw some flexibility for a deal between OPEC and non-OPEC.