Increasingly sophisticated thieves stole thousands of barrels per day of oil products from Mexico\'s state-owned oil company in the first four months of 2011, thefts worth about $250 million, the company\'s director said. Those thefts amounted to almost one million barrels in the first four months of the year, a level almost 50 per cent more than what thieves stole in the same period of 2010, according to the Petroleos Mexicanos oil company, also known as Pemex. Pemex director Juan Jose Suarez Coppel said the stolen fuel was the equivalent of 100 tanker trucks a day. \"Fuel theft has increased in the last few years,\" said Energy Secretary Jose Antonio Meade. \"The gangs that participate in these crimes are increasingly sophisticated, better organised and many times they have carried out these thefts using the latest technology.\" Mexican officials say drug cartels have been involved in the thefts, by tapping into state-owned pipelines. Thieves sometimes inject water into pipelines to cover up the drop in pressure caused by thefts or drill a second tap near the first to continue siphoning off oil if detected. Drilling into pipelines is dangerous due to the high pressure and combustibility of the fuel. While illegal pipeline taps have caused explosions, fires and spills in the past, authorities still find hundreds of successful taps each year. Suarez Coppel said 556 illegal taps had been detected so far in 2011, compared to 710 in all of 2010. Officials say drug cartels have been implicated in some of the thefts, especially in northern Mexico. Suarez Coppel said the largest number of thefts, about 150, occurred in Sinaloa state, considered the cradle of Mexican drug trafficking. He said the cartels may sell the fuel or even use it for their own vehicles. About 390 of the taps involved refined fuel pipelines, while about 135 were at ducts carrying crude. From / Gulf News