ExxonMobil Thursday reported slightly lower profits as weak refining margins offset the benefit of higher natural gas prices in the US that boosted earnings from petroleum production. Earnings for the first quarter came in 4.2 percent lower from the year-ago period at $9.1 billion. Exxon, the US's biggest oil company, again reported lower petroleumoutput, this time notching a decline of 5.6 percent from a year ago. However, exploration and production earnings still grew by 10.6 percent, thanks in part to a 49 percent rise in US natural gas prices in the wake of cold winter weather in much of the US. Exxon officials have emphasized that they will not sacrifice solid profit margins to keep production high. At the same time, analysts have been disappointed in how the slow ramp-up of many priority projects has meant lagging output. Earnings in the downstream portion of the business, which covers refining and the selling of gasoline, tumbled 47.3 percent from a year ago. Chemical earnings also fell, but by a smaller percentage. "ExxonMobil's first quarter earnings and cash flow reflect the company's continuing focus on delivering profitable growth and creating long - term shareholder value," said chief executive Rex Tillerson. "Strong performance in the upstream benefitted from improved production mix and increased un it profitability." Exxon's results translated into $2.10 per share, above the $1.88 forecast by Wall Street analysts. Revenues of $106.8 billion lagged forecasts of $109.8 billion. Shares of Dow member Exxon were up 0.3 percent to $102.75 in pre-market trade.