Ford called an emergency meeting with unions at its assembly plant in Genk, Belgium, amid mounting expectations that the U.S. automaker is preparing to close the factory.

Ford summoned staff representatives to a meeting with European executives at 0700 GMT (0300 EDT) on Wednesday without providing an agenda, officials from three unions said on Monday.

"No one is allowed to tell us anything," said an official with the ABVV Metaal union. "We're assuming it will be a very serious announcement."

A Ford spokesman declined to comment on the meeting or its purpose. "We will not comment on discussions with our unions," he said.

The plant in Genk, eastern Belgium, employs 4,300 workers to assemble the Mondeo mid-size car and Galaxy and S-MAX minivans. All three models are approaching the end of their current life cycles.

(Additional reporting by Andreas Cremer in Berlin; Editing by Christian Plumb)