(JTA) — Iran said it thwarted an attempted sabotage of tanks used for transporting heavy water to be used at its nuclear plants.

Asghar Zarean, the deputy chief in charge of nuclear protection and security for Iran’s Atomic Energy Organization, told Iranian media that the attempt took place two weeks ago at the Arak heavy-water production plant, according to international media reports.

Zarean said a “foreign country” was behind the sabotage try but did not specify which one.

“There were attempts to cause disruption in storage tanks due to carry heavy water,” he was quoted as saying. “But these attempts were discovered and foiled before the tanks were filled with heavy water at Arak.”

The heavy water reactor at Arak, which is a plutonium reactor, has not yet gone online.

Under an interim deal with the U.S. and other world powers, Iran agreed to roll back its work at Arak. The deadline for a permanent deal is Nov. 24.

The major powers have said that a permanent agreement would include disabling the plutonium reactor at Arak.