Construction work has intensified on a major new structure at a facility linked to Israel’s long-suspected atomic weapons programme, according to satellite images analysed by experts.

They say it could be a new reactor or a facility to assemble nuclear arms — but secrecy shrouding the programme makes it difficult to know for sure.

The work at the Shimon Peres Negev Nuclear Research Center near the city of Dimona will renew questions about Israel’s widely believed status as the Mideast’s only nuclear-armed state.

It could also draw international criticism, especially since it comes after Israel and the United States bombed nuclear sites across Iran in June over their fears that Tehran could use its enrichment facilities to pursue an atomic weapon.