VIENNA (AFP) - The OPEC oil producers cartel on Tuesday held steady its forecast for modest growth in world oil demand this year, noting uncertainty about the global economic outlook. Although the economic recovery shows signs of improving momentum, important risks remain that could impact demand growth expectations for this year, the Organization of Petroleum Exporting Countries said in its May report. The world oil demand forecast for 2010 will mostly depend on the performance of the United States economy, the report said. Should US oil demand weaken slightly and perform less than expected during the peak summer consumption season, then total world oil demand will be less than the current estimate. The cartel said it was expecting world oil demand growth to grow by 0.9 million barrels per day (bpd) or 1.1 percent to average 85.4 million bpd for 2010. That was almost unchanged from the previous report. The more cautious sentiment about the continued pace of the recovery has also been reflected in oil price volatility, OPEC said. US benchmark crude rose to more than 86 dollars per barrel before falling more than 10 dollars in three days. This strong volatility came despite the fact that crude fundamentals remain relatively unchanged and thus highlight the continued impact of financial market sentiment on crude oil prices, it said, pointing to Greece as an uncertainty factor. OPEC will continue to closely monitor the market, awaiting further signs that the positive momentum is broadening across all major regions.