Updated

Spain's heritage authority says preliminary technical work has resumed on the exhumation of the remains of four Spanish Civil War victims from a complex that pays homage to the late dictator Francisco Franco.

The four are believed to lie in crypts within the Valley of the Fallen, a controversial neoclassical mausoleum northwest of Madrid where thousands of victims in the 1936-1939 were buried alongside the remains of Franco himself.

Franco presented the grandiose complex as a symbol for national reconciliation, but victims' relatives have been campaigning to remove the bodies, arguing that the dictator's tomb is an insult to the victims' memory.

A judge ordered the exhumation of the first two victims in 2016, but the basilica's abbot stopped the work by appealing, until the Catholic Church hierarchy ordered him earlier this year to cooperate with authorities.