Dutch police detained more than 180 people on Monday night, when roaming groups set fires, threw rocks and looted stores in several cities.
The Netherlands' first curfew since World War Two was imposed on Saturday despite weeks of falling infections, after the National Institute for Health (RIVM) said a faster-spreading variant first found in England was causing a third of cases.
A hospital in Rotterdam warned visitors of patients to stay away, after rioters tried to attack hospitals in various cities in the past days.
A nationwide appeal issued by law enforcement authorities Tuesday evening called on parents to keep teenagers indoors, warning they could end up with a criminal record and forced to pay for "enormous damage to cars, shops and public property".
"We have had riots in the past, but it's rare to have this for several nights across the entire country," said National Police spokeswoman Suzanne van de Graaf. "It's not only in known problem areas, but much more widespread."