Chevron Corp. expressed interest in developing oil reserves straddling the Iran-Iraq border, potentially putting the American energy giant at risk of violating U.S. sanctions against Tehran, according to comments made public in a leaked diplomatic cable.

In the March 2009 cable, Iraqi Prime Minister Nouri al-Maliki told a senior U.S. embassy official he was in talks with Chevron about the cross-border oil field. He added that Chevron, America's second-largest oil company, had also approached Iran about the project - a claim the memo makes clear the embassy was unable to confirm.

Al-Maliki said Iraq was interested in awarding Chevron rights to develop the unnamed field but wanted the embassy's guidance about the political feasibility of such a deal in light of U.S. sanctions against Iran.

He prefers to go with Chevron on the deal; however, he remarked that if U.S. rules prevent Chevron from doing this project, he would approach a non-American firm, said the cable, which described a meeting led by Patricia Butenis, who was the Baghdad embassy's charge d'affairs at the time.

The cable was obtained by WikiLeaks and first reported by the Thursday edition of the British newspaper The Guardian. The U.S. has for years prohibited American oil companies from doing business with Iran through sanctions that are now aimed at thwarting Iran's disputed nuclear program. In the cable, Butenis told Maliki that U.S. law on sanctions would apply, but added that the Administration was reviewing its policies on Iran.

A Chevron spokesman in the Persian Gulf nation of Qatar referred questions to the company's San Ramon, California headquarters, which did not immediately respond to requests for comment.

Iraqi officials in Baghdad couldn't be reached.

An official at Iraq's state-run South Oil Co. in Basra said the talks with Chevron took place in 2009 and were focused on a cluster of three oil fields in the country's south. The fields, known as Missan, currently produce close to 100,000 barrels of crude a day and hold more than 2.6 billion barrels in reserves.

The oil official was granted anonymity to speak freely about the negotiations.

Earlier this year, Baghdad granted a consortium led by state-run China National Offshore Oil Corp. and its partner the Turkish Petroleum Corp. rights to develop the fields.