There is reason to believe that the 31-year-old from Syria intended to commit an act of terror in Copenhagen in November 2016, the judge found, and thereby extended the man's custody by a further four weeks.
The man, who is an asylum seeker in Sweden, was arrested on December 21st 2017.
Police believe he was working together with a 21-year-old compatriot who was given a prison sentence in Germany in 2017 in connection with the same case. The 21-year-old was sentenced to six and a half years in jail.
According to charges raised by Copenhagen Police against the 31-year-old, the pair planned to attack members of the public in Copenhagen with knives before then detonating one or more bombs.
The plans were foiled when the 21-year-old was stopped at the border with Denmark and later arrested by police in Germany.
During his trial in Germany, it was revealed that the Islamic State (Isis) terror group put the two individuals in contact with each other.
Evidence showed that the 21-year-old had declared himself prepared to kill in the name of Isis, the court in the German case heard.
“We must assume that there was an intention to detonate several bombs,” the judge in that court case said.
Prosecution lawyer Sonja Hedegaard declined on Monday to confirm when a decision would be made over whether the man will be indicted in the case.
Court proceedings in the case have thus far taken place behind closed doors. As such, the nature of evidence against him is unclear.