Updated

For the second time this week, the State Department rejected claims by Russian President Vladimir Putin that Turkey’s government is colluding with ISIS to smuggle oil across its borders.

“Our assessment is there is not a lot of smuggling happening of any significant volume between ISIL-controlled territories and Turkey,” said a senior department official speaking on background to reporters Friday.The official said he believed that smuggling operations have decreased over time and credited both the Turks and U.S. military strikes for making it harder for ISIS-controlled fuel trucks to gather in one place and smuggle oil inside Syria.

The official said 200-250 barrels of oil normally are transported per truck by ISIS. The official said it would take at least 1,000 trucks to smuggle enough oil across the border to make a difference in Turkey’s economy.

“The economics don’t make sense for that to happen,” he said. The official said there was no evidence to support “thousands of trucks” moving across the border.

Earlier this week, the Russian defense ministry showed satellite images and drone video purportedly showing trucks moving across the Syrian-Turkish border.

The official said the truck drivers would have to drive a long way across Syria to make it to the border, passing many checkpoints and making the journey both dangerous and expensive. The official compared the action to a New York City taxi driver taking someone to Newark and coming back to the city empty.

Still, the official acknowledged that “small amounts” of oil are smuggled, but “no significant volume.”

The official pointed to Syria’s President Bashar al-Assad as a main client of ISIS.

“There is a lot of [oil] trading with the regime,” the official said.

Since airstrikes began weeks ago from Turkey’s Incirlik Air Base by U.S. A-10 and AC-130 gunships, trucks no longer gather in one area the official said. But even after the destruction, the official said ISIS is being “very creative” about getting oil out of the ground.

When asked about the potential environmental damage to the oil wells via coalition airstrikes, the official said “we are sensitive to that,” when conducting airstrikes.

This was the second time this week the State Dept. has pushed back on the Russian government, despite the Russian defense ministry presenting satellite imagery and drone footage purportedly showing oil trucks crossing the Syrian-Turkish border.

“We reject outright the premise that the Turkish Government is in league with ISIL to smuggle oil across its borders, and we frankly see no evidence – none – to support such an accusation,” said Mark Toner, a State Dept. spokesman earlier this week.

The senior State Dept. official credited the Delta Force raid in Syria this past May that killed Abu Sayeff, known as the oil emir for ISIS, as bringing in “more data than any other operation has given us.”

When asked if the air campaign has had a significant impact on the Syrian population working for ISIS in their oil business, the official had a warning for anyone driving a truck or working at an ISIS-controlled facility.

“You should think twice before working there.”