MADRID (AP) — Activity in Spain's ports was intermittent Monday as dockworkers began a three-day strike to protest layoffs stemming from an effort to liberalize the industry in line with European Union rules.

Parliament passed a bill in May to end a decades-old monopoly by a workers' association on who gets employed to load and unload cargo at the country's 46 ports.

The government had been facing hefty EU fines for not reining in the restrictive practices earlier.

The ports handle 86 percent of Spain's imports and 60 percent of its exports. The strike is expected to have a noticeable impact on the economy.

The main national union said that most of the 6,150 dockworkers had stopped working Monday as planned, every other hour. Strikes are also scheduled for Wednesday and Friday this week.