JUBA (Reuters) - Several U.N. peacekeepers and civilian staff were killed in an ambush by unknown attackers in South Sudan's restive eastern state of Jonglei on Tuesday, the United Nations said.

"A number of peacekeepers were also injured in the attack," the U.N. Mission in South Sudan (UNMISS) said in a statement, without giving more details or the nationalities of the victims.

(Reporting by Andrew Green; Writing by Ulf Laessing in Cairo; Editing by Kevin Liffey)