 The EU insists on the strict adherence to convergence criteria (such as spending at least 2 years in the ERMII system) which are not negotiable before euro adoption, but have not intervened to stop the unilateral adoption of the euro by Montenegro in 2002.The issue is expected to be resolved through the negotiations process.The ECB has stated that the implications of unilateral euro adoption "would be spelled out at the latest in the event of possible negotiations on EU accession."