1.   The union threatened to call a strike.

2.   The union has threatened to call its members out on strike from midnight tomorrow.

3.   The union threatened a strike but called it off at the last minute.

4.   After the company announced plans to reduce benefits, the union threatened to retaliate by calling for a strike.

5.   The union has threatened a job action if wages are not increased.

6.   The union is threatening further industrial action.

7.   Although unions threatened protests and marches, there were no reports of strikes or disturbances.

8.   Bank deposits have receded, and unions are threatening another national strike.

9.   Also this week, two Nigerian oil workers unions threatened to disrupt oil exports starting Monday to press demands for payment of back wages.