The UN peacekeeping force in South Sudan said Thursday it had repulsed a "callous" attack by armed assailants on its base in the north of the country.

In a statement on Thursday, UNMISS said its Temporary Operating Base (TOB) in Leer town in the former Unity state came under small arms attack from the direction of the nearby government-held town on Wednesday between 11pm and midnight.

UNMISS further said the attack had been "carried out with callous disregard for the lives of civilians as well as UN and humanitarian workers".

It pointed out that the Ghanaian company of UNMISS peacekeeping forces based there quickly and robustly returned fire, deterring the attack.

The UN mission didn’t identify the attackers, but it indicated that the peacekeeping force fired from the direction of the nearby town of Leer, which is held by the government. There were no UNMISS or other casualties within the base from the attack.

"We strongly condemn the attack, and call on all parties to the conflict to respect the sanctity of UN premises," David Shearer, the head of the mission, said in the statement.

“We are here to protect and support the people of South Sudan,” he added. “It is clear the attackers have no consideration for their plight, given those who most desperately need help will suffer more because of a likely resulting delay of humanitarian aid.”

Government officials in the area were not immediately available for a comment.