The Arak IR-40 heavy water reactor in Iran. Photo: Nanking2012/Wikimedia Commons.

New satellite images of an Iranian nuclear site reveal that Iran may be close to producing weapons-grade plutonium, theTelegraph reported.

The images, taken Feb. 9, show steam rising from the Arak nuclear plant, an indication of heavy water production.

“The steam indicates that the heavy-water plant is operational and the extent of the air defence emplacements around the site make it suspicious,” said Stuart Ray of McKenzie Intelligence Services, who analyzed the photos on behalf of the Telegraph.

The Arak site is broken up into two components, one is the nuclear reactor site, which the International Atomic Energy Agency (IAEA) has been allowed to inspect, and the other is the heavy water site, which the IAEA has been barred from.

The release of the satellite photos come following nuclear talks between in Kazakhstan between Iran and the so-called P5+1 group, comprised of the five permanent members on the UN Security Council—the U.S., UK, France, Russia and China—plus Germany. According to the New York Times, the two days of talks ended with an agreement for further negotiations sometime in March over a proposal that would “sharply constrain Iran’s stockpile of the most dangerous enriched uranium.”