Saudi Arabia said on Sunday OPEC’s job in rebalancing the oil market was far from done as global inventories were still rising despite harsh U.S. sanctions on Iran and Venezuela, signalling it may need to expand output cuts into the second half of 2019.Russia, which is cutting oil output in tandem with OPEC, also said production cuts would stay in place at least until June, when Washington’s next steps on reducing Iran’s and Venezuela’s oil exports become clearer.The United States has been increasing its own oil exports steeply in recent months while imposing sanctions on Venezuela and Iran to reduce their shipments to global markets.Washington’s policies have introduced a new level of uncertainty for OPEC as it struggles to predict the balance of global supply and demand.OPEC and its allies have cut output by 1.2 million barrels per day - or 1.2 percent of global demand - since January to help rebalance the global oil market and prop up prices.......