Norwegian authorities have confirmed that two Norwegian nationals have leading positions within the Islamic State terrorist group, which has taken over swaths of Syria and Iraq, the country’s Aftenposten newspaper reported Wednesday, citing national broadcasting network NRK.

According to the report, the two Norwegians hold “commanding positions” and answer only to the head of the terrorist group, Abu Bakr al-Baghdadi, receiving orders directly from him.

The two Norwegians were named by the broadcaster as Bastian Vasquez from Skien, southwest of Oslo, and an unidentified Norwegian national of African descent from Bærum, just outside the Norwegian capital.

Vasquez reportedly appeared in an Islamic State propaganda video earlier this year, while the second Norwegian commander, who was not identified by name, was said to have left Norway for Syria in December 2012, nearly two years into the Syrian civil war.

The report quoted Norwegian security forces as saying more than 50 Norwegians have traveled to Syria to fight alongside rebel forces there — including al-Qaeda affiliates and breakaway jihadist groups.

Ten Norwegian nationals have reportedly been killed while fighting for the Islamic State, while 20 fighters have returned to Norway.

The presence of European fighters in the ranks of jihadists groups fighting in Iraq and Syria, most notably the Islamic State, has become a cause for concern for European states wary of the day they will try to return to their home states. These worries were amplified after Mehdi Nemmouche, who killed four people outside the Jewish Museum in Brussels, was discovered to have fought in Syria, and the Islamic State killer of US journalists Steven Sotloff and James Foley was suspected to be a British rapper.

In a video released by IS on Tuesday, a man with a London accent is seen brandishing a knife while standing next to a kneeling Sotloff before beheading him. A clip released two weeks ago showed what appeared to be the same man beheading Foley.

Although sources did not officially confirm the identity of the masked man, the Sunday Times reported (paywall) that a London-based rapper, Abdel-Majed Abdel Bary, 23, is a key suspect in the case.

Bary, whose songs have featured on BBC radio in the past, last year left his family’s house in Maida Vale, West London. He lived with his mother and five siblings in what was described as a “£1 million home.”

UK Foreign Secretary Philip Hammond was quoted by the Sunday Times as saying that Islamic State is “turning a swath of Iraq and Syria into a terrorist state as a base for launching attacks on the West.”

Hammond added that “sooner or later they will seek to strike us on British soil.”