ROME, Sept 8 (Reuters) - Italian bomb disposal experts safely exploded a device on Saturday left outside the Sardinian plant of Alcoa Inc., in an escalation of tensions over the U.S. aluminium producer's plans to shut down the factory.
The controlled explosion of the device, made up of eight sticks of what initially appeared to be gelignite, was broadcast on Italian television.
Italian news agency ANSA said it was also equipped with a fuse that could have allowed it to be set off remotely.
But that was not confirmed by a local police source, who said the nature of the package was still unclear. "The experts are still working to establish whether it could have exploded," the official told Reuters.
Bomb disposal experts were called after an anonymous caller told ANSA the device had been left outside the smelter at Portovesme on the Mediterranean island of Sardinia.
Prime Minister Mario Monti's government is under intense pressure from labour unions to save the unprofitable smelter at Portovesme.
It employs some 500 workers with a further 1,000 directly depending on the plant. Its closure would be a heavy blow for an island already beset by 15 percent unemployment.
Three workers spent three nights this week camped on top of a 60-metre (197-foot) water tower at the factory to protest against its gradual shutdown.
Alcoa said the progressive shutdown, which started on Sept. 1, would continue, but that the smelter would be maintained for another year "ready to be restarted by another operator, if one comes forward," according to a statement on Friday.
The firm is scheduled to meet in Rome on Monday with Italian officials and labour unions to discuss the plant's closure and any possible offers.