ISIS Reuters

Moroccan authorities said on Thursday that four suspects arrested following the murder of two young Scandinavian hikers in southern Morocco had pledged allegiance to the Islamic State (ISIS) jihadist group, AFP reported.

Three of the four suspects were arrested on Thursday over the grisly killing of the two hikers, as investigators probed a link to Islamic extremism.

"The video showing the arrested individuals... pledging allegiance to Daesh was recorded last week before the execution of the criminal acts we are investigating," the Rabat prosecutor said in a statement, using the Arabic acronym for ISIS and confirming the authenticity of the video.

Government spokesman Mustapha Khalfi described the killings as a "criminal and terrorist act", while Prime Minister Saad Eddine El Othmani called them a "stab in the back of Morocco and Moroccans".

That was in reference to the likely negative impact the murders will have on the North African country's vital tourism sector, which accounts for 10 percent of national income.

The interior ministry initially said that the two Danish and Norwegian hikers were found with cuts to their necks in an isolated mountainous area located 10 kilometers (six miles) from the tourist village of Imlil.

On Wednesday, a source told AFP that one of the women, who have been identified as 24-year-old Louisa Vesterager Jespersen from Denmark and 28-year-old Maren Ueland from Norway, had been beheaded.

The latest arrests in the city of Marrakesh follow a first arrest on Monday of a man suspected of belonging to an Islamic extremist group, hours after the discovery of the two women's bodies.

"The suspects have been arrested" and investigators were in the process of "verifying the terrorist motive, which is supported by the evidence and the findings of inquiries," said the central judicial investigations office.

In one of the black and white photos circulated by authorities, a suspect wears white robes and a white skullcap, and has a long beard.

The second suspect also has a long beard, while the third has a thin face and a goatee.

But in another picture released by police after they were detained, the three are freshly shaven and wearing plain clothes.

All three hail from Marrakesh, and one of them had "a court record linked to terrorist acts", police spokesman Boubker Sabik said.

Danish Prime Minister Lars Lokke Rasmussen denounced what he called a "beastly crime".

The most recent jihadist attack hit Morocco in 2011, when 17 people were killed in Marrakesh, including Israeli citizen Michal Weitzmann Zikri and her husband Masoud Zikri, a native of Morocco.

Previously, an attack in the financial capital Casablanca left 33 dead in 2003.

While Morocco has not been hit by terrorism in recent years, Moroccan authorities have arrested several suspects in connection with terrorist attacks in Europe.

In August of 2017, a man suspected of supplying gas canisters to a jihadist cell that carried out two terrorist attacks in Catalonia was arrested in Morocco.

A week earlier it was reported that Moroccan authorities had arrested two people suspected of links to the alleged perpetrators of an attack in Barcelona.