Most Islamic State illegal oil exports are probably conducted through Turkey and Kurdish areas, and are facilitated by corrupt regional officials, former Central Intelligence Agency (CIA) counterterrorism officer and US Senate Foreign Relations Committee senior investigator John Kiriakou told Sputnik.

WASHINGTON (Sputnik) — A US Treasury Department spokesperson told Sputnik this week that the Islamic State has made about $40 million in one month of oil sales, making close to $500 million a year.

"I’ve always assumed someone on the Turkish side of the border is making enough money out of it. There are too many vested interests involved for it to stop," Kiriakou said on Thursday. "They greased the right people. Someone’s making a lot of money out of this."

Kiriakou noted that the current Islamic State illegal oil trade followed the same basic pattern that longtime Iraqi dictator Saddam Hussein used to defy international economic sanctions.

"[Selling and transporting oil] thorough Turkey was the way Saddam Hussein for years beat the sanctions regime imposed on him," the expert said.

Turkey is an ally of the United States and has been a member of NATO for 60 years, but Kiriakou said the national government in Ankara could not prevent the corruption of local officials in outlying regions that enabled the secret oil trade.

"It’s not the official Turkish government. [It’s] probably corrupt elements of the Turkish military and officials in local and regional governments in southwest Turkey who are involved in this," he explained.

The US government has the resources to seriously reduce and interdict this lucrative oil traffic, but so far has failed to focus on doing so, Kiriakou argued.

"It’s a question of priorities. They have never allocated enough resources to do so. Other goals and missions have been rated as having more urgent calls on intelligence and tactical resources," he said.

However, Kiriakou told Sputnik that the Islamic State oil revenue lifeline could certainly be cut if Washington was determined to do so.

"I do believe that," he insisted.

The richest oil fields that the Islamic State can access are south of Irbil in Iraq and the most obvious direction for the Islamic State to move the oil is westwards through Kurdish territory, Kiriakou explained.

In Saddam Hussein’s time, most of the oil secretly exported from Iraq to defeat the international sanctions regime was moved west through Kurdish territory, and that pattern is probably continuing now, he suggested.

Washington, he added, should be cooperating closely with Russia in cutting the Islamic State’s oil revenue flow.

"We should be working with the Russians to achieve a settlement of the conflict in Syria. We have basically the same aims that they do. Both of us agree that the Islamic State is a bad idea and we both want to get rid of it. But we’re not working with them on this," Kiriakou said.

Iraq's Oil Ministry told Sputnik that the Islamic State continues to sell hundreds of thousands of barrels of oil per day on the black market.