Israel’s antitrust authority said Tuesday it will challenge the ownership structure of the country’s natural gas resources, a decision that could rattle an increasingly important industry.

A conglomerate of companies including Texas-based Noble Energy and Israel’s Delek Group has been developing Israel’s offshore natural gas deposits, selling gas to the Israeli market and agreeing to sell to neighboring countries as well.

In an earlier understanding with the antitrust authority, the conglomerate agreed to sell two smaller gas fields to avoid a monopoly. But the authority said Tuesday it was scrapping that deal, seeing it as insufficient.

In a statement, the authority said it was aware of the potential risks to the economy prompted by its decision but chose to move ahead because “a thorough approach is needed in order to provide a real solution to the problem of a monopoly in the market.”

The authority said it is considering a new agreement, which could strip the conglomerate of its bigger, more lucrative fields.

The conglomerate says it has invested billions of dollars developing the fields and will oppose the decision.

“We invested according to Israeli law, according to the highest global standards. We will fight forcefully for the rights we were granted by the Israeli government,” said Binyamin Zomer, the head of Noble Energy Israel.

Noble and its Israeli partners own the Tamar field, which is online, as well as the larger Leviathan field, which contains an estimated 530 billion cubic meters of gas and is expected to begin production in 2018.

Critics say the government has allowed the conglomerate to profit excessively.

“A situation in which all of Israel’s natural gas is under the control of a private corporation crosses the lines of economic and democratic reason,” Shelly Yacimovich an opposition lawmaker, wrote on her Facebook page.