The Netherlands was hit by continued wave of riots on Monday evening, as protesters again went on the rampage in several cities following the introduction of a COVID-19 curfew over the weekend.

A man rests on his broom as he stands next to shards of glass and smashed windows of a fast-food restaurant that was damaged in protests against a nationwide curfew in Rotterdam, Jan. 25, 2021.

Riot police clashed with groups of protesters in Amsterdam as well as the port city of Rotterdam, where people smashed shop windows and ransacked their supplies.

A bin and a bicycle burns as groups of local youth gather on the streets of Schilderswijk on Jan. 25, 2021 in The Hague, Netherlands.

The unrest also hit Amersfoort in the east, the small southern city of Geleen near Maastricht, The Hague and Den Bosch, police and news reports said.

Police officers detain a man during a protest against coronavirus restrictions in Amsterdam, Jan. 24, 2021.

More than 70 people had been rounded up by 10 p.m. GMT, public newscaster NOS reported.

Anti-riot forces gather as groups of local youth gather on the streets of Schilderswijk Jan. 25, 2021 in The Hague, Netherlands.

In Rotterdam, police used a water cannon after clashing with the protesters, the NOS said. The city's mayor, Ahmed Aboutaleb, issued an emergency decree which gave police broader powers of arrest. "There is an urgent request to all to leave the area," the city council said on Twitter.

Police officers arrest a suspect as groups of local youth gather on the streets of Schilderswijk on Jan/ 25, 2021 in The Hague, Netherlands.

Images on social media showed rioters looting a shop in Den Bosch and a press photographer being hit in the head in Haarlem after an angry mob chased him off and threw a brick at him.

Business owners barricade their shops in fear of possible looting on Jan. 25, 2021 in Nijmegen, Netherlands.

Earlier Prime Minister Mark Rutte had condemned what he called the "criminal violence" of the previous night, which police officials described as the "worst rioting in 40 years."

The burned car infront of Eindhoven Centraal, central train station.

Police arrested around 250 people after using water cannon and tear gas during demonstrations in Amsterdam, Eindhoven and other towns on Sunday, local media said.

Roadblock made of bicycles recently distinguished them in Eindhoven.

Late Monday, mayors in several Dutch cities announced they would introduce emergency measures to try and prevent further rioting. On the first night, rioters had looted shops, burned cars and torched a coronavirus testing station after the country's first curfew since World War II took effect late Saturday.

The remains of a car that was turned over and set ablaze are seen near Eindhoven Central Station.

"It's unacceptable. All normal people will regard this with horror," Rutte told reporters. "What motivated these people has nothing to do with protesting; it's criminal violence, and we will treat it as such."

A man wearing a billboard against vaccines reacts in front of a police officer during a protest against restrictions in Amsterdam, Netherlands Jan. 24, 2021.

In Eindhoven, where businesses were looted and a car torched, Mayor John Jorritsma likened the situation to "civil war" and called for the army to be sent in. And Rutte condemned the "idiots" who pelted a hospital in the town of Enschede with stones.

A man is dressed as death during a protest against restrictions in Amsterdam, Jan. 24, 2021.

Violators of the 9 p.m.-to-4:30 a.m. curfew, which is set to last until at least Feb. 10, face a 95 euro ($115) fine. Exemptions are allowed, for example, for people having to work, attend funerals or walk their dogs, on condition that they present a certificate.

A demonstrator throws a sign during a protest against restrictions in Amsterdam, Netherlands Jan. 24, 2021.

The Netherlands was already under its toughest measures since the start of the pandemic, with bars and restaurants having closed in October, and schools and nonessential shops shut since December.

A garbage container and bicycles are seen burning on the street.

More than 13,500 people have died in the Netherlands since the start of the COVID-19 pandemic.

A firefighter extinguishes a container that was set alight during protests in Rotterdam.

While the rate of new infections has been slowing, growing fears over new, more infectious strains of the virus prompted the government to announce the curfew.

A person looks at a torched coronavirus testing facility in the Dutch fishing village of Urk, Sunday, Jan. 24, 2021.

Police Union chief Koen Simmers on Monday told NOS that police were prepared should the rioting continue. "I hope it was a one-off, but I'm afraid it could be a harbinger for the days and weeks to come," Simmers said.

Glaziers remove broken glass at a supermarket after yesterday's riots against the COVID-19 lockdown in Eindhoven, Jan 25. 2021.