Riot police have held back striking Lisbon dock workers while port operators remove ship containers stranded for several weeks by the walkout over pay and labor rights.

Dozens of striking stevedores gathered outside gates at Lisbon's port Tuesday and shouted at what they said were strike-breakers helping to load the containers on trucks.

The dock workers and shipping companies operating at the port failed to break the deadlock in their latest talks on Friday, and seven companies said would begin lay-offs to compensate for lost income. The companies say they have lost around 10 million euros ($11 million) so far due to the strike.

The Stevedores' Union is demanding greater job security and automatic promotions every three years, as well as higher pay. Union leaders said the strike would continue.