* Antwerp plant set to close by end of year
* Potential investors did not meet company's conditions
(Updates with Opel confirmation)
BRUSSELS, Oct 4 (Reuters) - Opel's car assembly plant in Antwerp, Belgium, will close at the end of the year after a search for an outside investor ended without success, the carmaker said on Monday.
Owner General Motors initially announced in January that the plant, with 2,600 workers, would close in 2010 with a further 8,300 job cuts elsewhere as auto demand weakened in Europe.
It later said the Belgian plant, whose workforce has since halved, might have a future if an investor were found by the end of September.
But Opel said in a statement that it had not received any adequate proposals.
"Consistent with our known restructuring plan, we will continue production in Antwerp until the end of this year. After then, production will cease and the plant will be closed," Opel said.
The company remained open to discuss any reasonable proposal during the wind-down period, but its active search for an investor had ended, Opel said.
Antwerp is set to be the first major European assembly plant to close since Peugeot shut down Ryton in Britain and Opel ended operations at Azambuja in Portugal. Both were announced in 2006. (Reporting by Philip Blenkinsop; Editing by Sharon Lindores)