The Spanish Civil Guard said on Wednesday it had received a threat that bombs had been placed on highways in the eastern Valencia region.
The National Police said they were investigating reports of the threat.
A civil guard spokesman told Reuters he had no information about a newspaper report that a bomb claimed by the Basque separatist group ETA had gone off.
El Publico newspaper reported on its web site that four bombs had been planted on roads and railways. It initially said one had exploded but later retracted that report. (Reuters)