OPEC and its allies agreed in principle to raise crude-oil output by 548,000 barrels a day in September, delegates said after a short videoconference on Sunday. The decision would complete the unwinding of 2.2 million barrels a day of voluntary curbs adopted last year by eight core members of the producer group. Ministers also plan to reevaluate a separate 1.66 million-barrel-a-day supply restraint by the end of December, leaving open the prospect of further increases as the market approaches what analysts expect will be a surplus later in the year. The alliance scheduled its next policy meeting for 7 September to review market conditions and finalize the September increase.