Dutch riot police have arrested more than 30 in a wave of unrest since protests on July 16 shut down two ports and descended into flames.
The unrest, involving hundreds of rioters, is the worst faced by the Netherlands since 2005, when 31 people were killed in rioting that also spread to Amsterdam and Rotterdam.
The latest violence marks an escalation of tensions as Dutch society and the country’s larger economy grapple with the legacy of the financial crisis and the dependence of much of Dutch industry on trade with the crisis-stricken Mediterranean countries.
The rioting took place overnight on Thursday in Rotterdam and was said to have ended early Friday in the city where 100 officers were deployed. No injuries were reported.
Police said in a tweet that the unrest had subsided in the early hours of Friday morning.
On Thursday, they said more than 16,000 calls to a hotline advising people of their rights were made by 1:00 a.m. local time, with 52 arrests. A number of protesters were also injured and several were arrested, they said.
Some protesters gathered overnight Thursday in Rotterdam and then clashed with police in the early hours. Riot police in full gear swarmed the streets, jostling with protesters in the early hours of Friday.
As the rioting spread to the neighboring city of The Hague, clashes erupted in a central shopping area.
Dutch media reported that police were trying to disperse a standoff.
The unrest continued on Thursday in a number of cities, with the website De Telegraaf reporting that several hundred demonstrators had marched through the center of Rotterdam.
As well as impeding access to ports for shipping companies, the protests stopped vessels leaving the Port of Rotterdam to leave for Egypt, including one scheduled to sail for Gaza.
The demonstrations and subsequent blockades have triggered fears of food shortages in the Netherlands as a result of the closure of the ports, according to De Telegraaf.
“Some massive food imports from Spain and the rest of the Mediterranean could have problems getting to Netherlands, and for that reason I am very worried,” said Arthur van der Veen, president of the Netherlands Federation of Caterers.
“We have a large market area with 81 supermarkets. The price of some of the ingredients we buy is being boosted by the fear of not having access to containers.”
Lise Lijnbaan, the Dutch chief of customs, said on Twitter that exports and imports had fallen by 1.8 percent and 13 percent respectively after the ports of Rotterdam and The Hague were closed.
Business intelligence firm Insight Solutions Europe said the protests and delays could cost up to $2.3 billion in lost exports and imports.
Rotterdam, the Netherlands’ main port, accounts for 17 percent of all Dutch exports.