Israel’s antitrust authority said Monday it may revoke an arrangement permitting an Israeli and a U.S. company to develop Israel’s largest natural gas field by branding them a cartel. The authority summoned representatives of Israel’s Delek Group and Texas-based Noble Energy and told them it was « still considering to announce that buying Leviathan was illegal. « We didn’t make any decision today, » an authority spokesman said after the meeting had ended. Anti-trust authorities have been targeting the companies, which discovered the field and two others, after criticism that the firms have too much control of such valuable national assets. Israel’s Channel 2 television said the authority had told Israeli gas tycoon, Yitzhak Tshuva, who has a controlling stake in Delek, that it « was weighing the possibility it may seize » the Leviathan field, the world’s largest offshore gas find of the past decade, with reserves of 22 trillion cubic feet. The spokesman said taking Leviathan, located off Israel’s Mediterranean coast, from Delek and Noble was « the most radical option » available and that other ideas were being considered. Tshuva told Channel 2 « all our interest has been is for the gas to flow as quickly as possible… » The dispute over allowing the companies sole control over developing the gas field has been brewing for about three years. It is a hot-button issue in a campaign for a March election focussed on economic issues such as high living costs. Liberal politicians seeking to defeat Prime Minister Benjamin Netanyahu accuse his government of permitting tycoons an unfair monopoly over Israel’s greatest natural resource. Earlier this year Delek said it was negotiating for regulators to approve continuing operations in Leviathan in return for selling its stakes in two adjoining fields, Tanin and Karish, with combined estimated reserves of 3 trillion cubic feet. Noble’s shares fell 0.5 percent in New York, while Delek’s shares slipped 6.3 percent in Tel Aviv. Production of Leviathan is expected to begin by 2018 and initial investment could reach an estimated $6.5 billion. Leviathan partners are in talks with Britain’s BG Group , which wants gas to feed its Egyptian LNG export plant, and with Jordan’s national electricity company. Talks to bring in Australia’s Woodside Petroleum, a liquefied natural gas (LNG) specialist, fell through in March. Noble owns 39.66 percent of Leviathan. Delek Drilling and Avner Oil Exploration – both units of Delek Group – hold 22.67 percent each and Ratio Oil Exploration owns 15 percent. Delek and Noble also hold major stakes in the Tamar field, which is near Leviathan and started production nearly two years ago.