At least 34 children have died in rebel-held Syria after being injected with contaminated measles vaccines, the rebel government said on Tuesday, warning that the deaths might be caused by saboteurs linked to the Assad regime.

The death toll is expected to rise, with many children from eight towns in Idlib province, north-west Syria, still in intensive care on Tuesday night.

Parents accused opposition health authorities of failing to store the vaccines properly, and of supplying out-of-date medication. But opposition officials denied accusations of negligence, saying that the vaccines came from Unicef and WHO, via the Turkish government, and that the same batch had successfully vaccinated 60,000 schoolchildren in 30 locations in recent days.