LONDON OPEC heavyweight Saudi Arabia said the oil producers' cartel was heading toward another production cut when it meets next week but that the magnitude of the cut was undecided, a Saudi official said on Friday. "There is a very strong possibility of an output cut but all options are open regarding the size of the cut," the source told Reuters. He said the Organization of the Petroleum Exporting Countries and other oil producers will continue to discuss the market outlook before a final output level would be decided. Saudi Oil Minister Ali al-Naimi met his Mexican counterpart Ernesto Martens on Saturday and on Monday, March 12 he will meet Venezuelan Oil Minister Alvaro Silva in Riyadh before heading to Vienna for the March 16 OPEC meeting. Recent comments from officials of Saudi Arabia, Iran, Indonesia and Qatar have lent weight to speculation that OPEC will reduce production by between 500,000 and one million barrels per day (bpd). It implemented a 1.5 million bpd in February to ward off any price slide during the seasonal demand downturn in the second quarter. But the cartel, spooked by forecasts of a global economic slowdown eating away growth in petroleum demand, will have a delicate task deciding how much OPEC can lop off output without harming a fragile world economy.