KARACHI (Reuters) - Pakistans consumer price index (CPI), the key indicator of inflation, likely rose by 12.6 percent year-on-year in April because of a rise in petroleum prices, according to a Reuters poll. April consumer prices were seen rising 12.6 percent from a year earlier, according to the median of a survey of 12 analysts and economists. The CPI rose by 12.91 percent in March from a year ago. The Federal Bureau of Statistics is due to release CPI data on, or soon after, Monday. +ACI-The aftershocks reverberating from the recent petroleum products price increase are more likely to make their impact felt on the CPI inflation for April 2010,+ACI- said Khalid Iqbal Siddiqui, director of Invest and Finance Securities Ltd. Analysts said inflation could exceed 13 percent by the end of the 2009/10 (July-June) fiscal year and the central bank is likely to maintain a tight monetary policy. +ACI-CPI inflation could potentially shoot back up over 13 percent once again to close out the fiscal year,+ACI- said Siddiqui. +ACI-Therefore the SBPs (State Bank of Pakistan) next monetary policy statement is likely to be cognizant of this expectation.+ACI- The SBP in March kept its key policy rate unchanged at 12.5 percent for April and May amid worry about persisting inflationary pressure and a widening fiscal deficit. It forecast 2009/10 CPI inflation could average between 11.0 and 12.0pc.