At least seven people have been killed in an attack on a UN vehicle in Garowe, the capital of Puntland in northeastern Somalia, local security sources told Al Jazeera.

Four UNICEF staff members were among the dead and four other staff members were in a serious condition, the United Nations Children's Fund said in a statement on Monday.

Abdiwali Hirsi, Puntland's Information Minister, told Al Jazeera that two other victims were Somali security guards. The seventh victim was yet to be identified.

UNICEF said the attack occurred when the vehicle travelled from a guest house to the UN agency's office in Garowe in the autonomous Puntland region, adding that the UN was presently contacting families of the staff and airlifting the injured.

The victims were an integral part of UNICEF’s work in Somalia, "dedicated to improving the lives of others", the statement said.