Vienna - The price for crude oil produced by the Organization of the Petroleum Exporting Countries (OPEC) fell below 139 dollars a barrel on Monday, data released by OPEC on Tuesday showed. 

One barrel (159 litres) of OPEC-produced crude stood at 138.44 dollars Monday, down 1.69 dollars from 140.13 dollars last Friday. 

OPEC calculates an average basket price based on 13 important brands produced by cartel members. (dpa)