BBC News | Oil prices in reverse amid Opec call BBC News Oil prices tumbled again on Monday, eroding last week's gains, as Opec called for co-operation from oil-producing nations outside the cartel. Brent crude fell 3% to $31.25 a barrel following a 10% surge on Friday, while US oil was $1.02 lower at $31.17. MarketsOpec secretary general calls for talks on oil price collapse OPEC sec-gen urges non-OPEC to help clear oil stocks overhang OPEC's El-Badri Calls on Global Oil Producers to Help Curb Glut |