Israel believes Syria has retained caches of combat-ready chemical weapons after giving up raw materials used to produce such munitions under pressure from foreign powers, a senior Israeli official said on Thursday.

Summarizing Israeli intelligence estimates that were previously not disclosed to avoid undermining the Syrians’ surrender of their declared chemical arsenal, the official said they had kept some missile warheads, air-dropped bombs and rocket-propelled grenades primed with toxins like sarin.

“There is, to my mind, still in the hands of Syria a significant residual capability … that could be used in certain circumstances and could be potentially very serious,” the official told Reuters on condition of anonymity. […]