Moroccan police have arrested a further nine people over the killing of two Scandinavian women whose bodies were found in a remote part of the Atlas mountains after an attack described as motivated by terrorism.
Authorities initially detained four suspects after the bodies were found on Monday and said they were the same men seen pledging allegiance to ISIS in a video circulated on Twitter.
In the video, the suspects threatened to carry out attacks, Morocco's general prosecutor on Thursday. Investigations showed the video was made in the week before the women were killed.
The bodies 24-year-old Louisa Vesterager Jespersen of Denmark and 28-year-old Norwegian citizen Maren Ueland were discovered on Monday with knife wounds in their necks.
Norwegian police said on Friday that another video purportedly showing the killings was probably authentic.
"There is no concrete evidence indicating the video is not real," Norway's National Criminal Investigation Service said.
Commenting on the video in which the suspects pledge allegiance to ISIS, the NCIS said that "neither Norway nor Denmark was mentioned in the video, nor was there anything specific about what action they should perform".
The slain women lived in southern Norway, where they attended university.
The NCIS said it was trying to trace the women's movements before their left for Imlil village, a common starting point for treks to Mount Toubkal, North Africa's highest peak. Their bodies were found about 10 kilometres from the village.
The slayings have shocked Morocco, a popular tourist destination where attacks on foreigners are extremely rare. In the capital of Rabat, government spokesman Mustapha El Khalfi said Morocco condemned "this terrorist, criminal act".
"It is an unacceptable act that does not fit with the values and traditions of Moroccan people nor the traditions of the area where the crime happened," Mr El Khalfi said.
Three of the suspects were arrested on Thursday while they were trying to leave Marrakech on a bus, Moroccan national security spokesman Boubker Sabik said. The first suspect was arrested on Tuesday, and authorities are not pursuing others besides the four, he said.
Morocco is generally considered safe for tourists but has battled with Islamic extremism for years. More than a thousand Moroccans are believed to have joined ISIS.
An anti-terrorism rally is being planned for Saturday in Rabat.