The judgments were reached by David Albright, a former UN weapons inspector who heads the Institute for Science and International Security research group and Decker Eveleth, an associate research analyst at CNA, a Washington think tank.

They told Reuters separately that Israel struck Parchin, a massive military complex near Tehran on Saturday. Israel also hit Khojir, according to Eveleth, a sprawling missile production site near Tehran.

Reuters reported in July that Khojir was undergoing massive expansion.

Eveleth said the Israeli strikes on Saturday may have "significantly hampered Iran's ability to mass produce missiles".

The Israeli military said three waves of Israeli jets struck missile factories and other sites near Tehran and in western Iran early on Saturday in retaliation for Tehran's October 1 barrage of more than 200 missiles against Israel.

Iran's military said the Israeli warplanes used "very light warheads" to strike border radar systems in the provinces of Ilam, Khuzestan and around Tehran.

Iran has the Middle East's largest missile arsenal and supplied missiles to Russia to use against Ukraine and to Yemen's Houthi rebels and the Lebanese militia Hezbollah, according to US officials.

Tehran and Moscow deny that Russia has received Iranian missiles.

Planet Labs imagery reviewed earlier this year by Eveleth and Jeffrey Lewis of the Middlebury Institute of International Studies at Monterey showed major expansions at Khojir and the Modarres military complex near Tehran that the pair assessed were for boosting missile production, Reuters reported.

Three senior Iranian officials confirmed that conclusion.