TEHRAN – Iranian Foreign Minister Mohammad Javad Zarif has criticized several Western leaders and the UN nuclear watchdog over their silence on Israeli nuclear activities.

Zarif mentioned U.S. President Joe Biden, French President Emanuel Macron, British Prime Minister Boris Johnson, German Chancellor Angela Merkel, and the International Atomic Energy Agency.

“Israel is expanding Dimona, the region's only nuclear bomb factory. @POTUS @iaeaorg @BorisJohnson @EmmanuelMacron Angela Merkel. Gravely concerned? Concerned?  A little? Care to comment? I thought so,” the Iranian chief diplomat said in a tweet Saturday.

The tweet came after Western news organizations reported that Israel is expanding its Dimona nuclear plant, where Israel has made material for nuclear bombs.

“Israel is carrying out a major expansion of its Dimona nuclear facility in the Negev desert, where it has historically made the fissile material for its nuclear arsenal,” The Guardian reported, citing Satellite images that show significant expansion of the desert site over the past few years.

According to the British newspaper, construction work is evident in new satellite images published on Thursday by the International Panel on Fissile Material (IPFM), an independent expert group.

The area being worked on is a few hundred meters across to the south and west of the domed reactor and reprocessing point at the Shimon Peres Negev Nuclear Research Center, near the desert town of Dimona, the newspaper continued.

Pundits believe that the construction work has begun in early 2019.

“It appears that the construction started quite early in 2019, or late 2018, so it’s been underway for about two years, but that’s all we can say at this point,” Pavel Podvig, a researcher with the program on science and global security at Princeton University, said.

The Israeli embassy in Washington refused to comment on the new images. Israel has a policy of deliberate ambiguity on its nuclear arsenal, neither confirming nor denying its existence. But pundits believe that the Israeli regime does possess weapons of mass destruction. Israel also refuses to cooperate with the international community on its nuclear program.