Suspected ISIL fighters have killed at least six Afghan employees of the International Committee of the Red Cross (ICRC) engaged in carrying supplies in the north of the country to areas hit by deadly snow storms, according to government officials.

Another two employees were unaccounted for after Wednesday’s attack in Jowzjan province, said Thomas Glass, ICRC spokesperson. The ICRC said it did not know who was responsible for the attack.

Confirming the report, Lotfullah Azizi, the Jowzjan governor, told Reuters news agency the aid workers were in a convoy that was carrying supplies to areas hit by avalanches when they were attacked by men belonging to ISIL, or the Islamic State of Iraq and the Levant group.

“Daesh is very active in that area,” Azizi said, using an alternate name for ISIL, also known as ISIS, which has made limited inroads in Afghanistan but has carried out increasingly deadly attacks.

Rahmatullah Turkistani, Jawzjan police chief, said the workers’ bodies had been brought to the provincial capital and a search operation launched to find the two missing ICRC employees.

Zabiullah Mujahid, Taliban spokesperson, told Al Jazeera that the group was not involved in the attack.

Last month, a Spanish ICRC employee was released less than a month after he was kidnapped by unidentified attackers in northern Afghanistan.

That staff member was travelling with three Afghan colleagues between Mazar-i-Sharif and Kunduz on December 19 when gunmen stopped the vehicles.

The other Afghan ICRC staff were immediately released.

In a recent summary of its work in Afghanistan last year, the ICRC said increasing insecurity had made it difficult to provide aid to many parts of the country.

“Despite it all, the ICRC has remained true to its commitment to the people of Afghanistan, as it has throughout the last 30 years of its continuous presence in the country,” the statement said.

In April 2015 the bullet-riddled bodies of five Afghan workers for Save the Children were found after they were abducted in the southern province of Uruzgan.