Former U.S. President Jimmy Carter has said Israel holds at least 150 nuclear weapons, the first time a U.S. president has publicly acknowledged Israel’s atomic arsenal.

Asked at a news conference at Wales’s Hay literary festival how a future U.S. president should deal with the Iranian nuclear threat, Carter put the risk in context by listing atomic weapons held globally.

“The U.S. has more more than 12,000 nuclear weapons, the Soviet Union (Russia) has about the same, Great Britain and France have several hundred, and Israel has 150 or more. We have a phalanx of enormous weaponry … not only of enormous weaponry but of rockets to deliver those missiles on a pinpoint accuracy target,” he said, according to a transcript of his remarks.

Carter also condemned Israel’s blockade of the Gaza Strip as “one of the greatest human rights crimes now existing on Earth,” according to the Agence France-Presse news agency.

Carter said in reference to the situation of Palestinians in Gaza that, “There is no reason to treat these people this way.”

The 83-year-old was subjected to criticism on a recent visit to Israel for his meetings with officials from Palestinian militant group Hamas as well as his trip to Syria where he met with Syrian President Bashar Assad and Hamas leader Khaled Meshal.

He has also in the past branded a “crime and an atrocity” the Israeli blockade of Gaza, imposed in response to ongoing rocket attacks launched from the territory.