The Rabat public prosecutor’s office did not name the group in a statement on Wednesday.
The women’s bodies were found on Monday in an isolated area near Imlil, on the way to Toubkal, North Africa’s highest peak and a popular hiking destination.
The suspect was arrested in Marrakech, Morocco’s main tourist hub on Tuesday and police were hunting other individuals identified as suspects.
“We are working to bring before justice three other suspects on the run,” said police spokesperson Boubker Sabik.
The two tourists, Louisa Vesterager Jespersen, 24, of Denmark and 28-year-old Maren Ueland of Norway, were killed in an unguarded area in hard to reach mountains, he said.
Investigations are also going on to authenticate a video tape shared on social media claiming to show the killing of one of the tourists, the general prosecutor said in a statement.
The video purportedly showed the killing, with a woman screaming while a man cuts her neck with what appears to be a kitchen knife.
A source from Imlil said one of the victims was found dead inside her tent while another was found outside.
Citing a security source, Morocco’s public TV channel 2M said on its website that investigations showed that the slaying of the two tourists was related to armed groups.
Moroccan media outlets reported that investigators have video surveillance footage showing three suspects putting up a tent near the victims’ tent and leaving the area after the slaying.
Authorities in Denmark and Norway warned their citizens from hiking without local guides in Morocco after the killing. Danish police officials said on Wednesday they sent an officer to Morocco to assist in the investigation.
Maren Ueland’s mother, Irene Ueland, told Norwegian broadcaster NRK her daughter had taken safety precautions before making the trip.
Jespersen’s mother told tabloid BT that the family had warned her against undertaking the journey.
The University of South-Eastern Norway said on its website that both women were studying to earn bachelor’s degrees in outdoor life, culture and ecophilosophy. They attended a campus in Boe, southern Norway and west of Oslo.
“What we know is that they were on a monthlong, private holiday in Morocco. Our thoughts go to the families,” the university said on its home page, adding flags were flown at half-staff in their memory Tuesday.
Morocco has been largely insulated from the attacks by armed groups that have plagued other countries in North Africa.
The latest bomb attack in the country dates back to April 2011 when 17 people were killed in a restaurant in Marrakech.
Morocco has stepped up its effort to counter armed groups with the creation in 2015 of its own version of the FBI. The Central Bureau for Judicial Investigations has so far broken up 57 cells of armed groups, including eight in 2018.
More than 1,000 Moroccan youths, predominantly from the north of the country, have joined armed groups in the Middle East.