Belgian workers kept six executives of world steel giant ArcelorMittal locked up in their office for more than 24 hours until Tuesday over union demands for the reopening of blast furnaces.
The managers were allowed to leave their fourth-floor office in the southern city of Liege on Tuesday afternoon after angry workers holding a protest had prevented them from leaving since Monday morning.
Unions decided to let them go after a "rocky meeting" during which some workers wanted to keep the executives sequestered, David Camerini, an official of Christian Union (CSC), told AFP.
One of the executives, Etienne Botton, said they were kept in "terrible" conditions.
"We had to sleep on the floor and were woken up regularly," Botton said. "Yesterday, we ordered pizzas but the boxes were empty when they arrived."
The executives were not physically attacked and were able to eat Tuesday morning, he added.
Camerini said the unions decided to release the executives to prevent tensions from rising but they would continue strikes at ArcelorMittal in Liege, where 3,000 people are employed by the group.
Unions want the company to restart activity at two blast furnaces and keep 300 interim workers employed.
Arcelor Mittal wants to keep only 200 workers at the furnaces and said it would only return to the negotiating table when the executives in Liege are freed.
Based in Luxembourg, ArcelorMittal is run by Indian chairman and chief executive Lakshmi Mittal