U.S. automaker General Motors(GM) says that its ailing South Korean unit will file for bankruptcy if its union does not make concessions by April 20th.

Barry Engle, president of GM International, made the comment on Monday during a meeting with GM Korea’s union. 

The executive urged the union to at least strike a provisional deal on a wage package by the end of this month, saying that without the agreement, GM could not present its self-rescue plan to the Seoul government by April 20th.

Engle said that GM Korea would need about 600 billion won by the end of next month to pay for early retirement benefits, but without further state support it doesn't have the money. 

He said that if the Seoul government vows to provide support for GM Korea, GM would implement its promises, but it would not provide the 600 billion won unless the union reaches an agreement.