"Our assessment of the situation in Denmark remains unchanged. The terror threat continues to be serious and an increased emergency already in place," DSIS said.
"We are closely overviewing the situation after Nice last night, we continue to evaluate the consequences of the terror attack in France regarding the threat image in Denmark," the security agency added.
Late on Thursday evening, a heavy truck hit a crowd celebrating the Bastille Day in Nice, killing 84 and injuring dozens more.
The driver was shot dead by police. According to ID documents found inside the truck, he was a 31-year-old man who was a resident of Nice of Tunisian origin. It is unclear whether he had any accomplices.