Five members of a U.N. peacekeeping mission in South Sudan, known by its initials UNMISS, were killed while on patrol on Jonglei, the country's largest state. Two civilian staff members and five other civilians escorting their convoy were killed by armed groups during the attack Tuesday.
Catherine Ashton, the top foreign policy chief for the European Union, issued a statement through her office condemning the loss of life.
"(Ashton) deplores the ongoing conflict in Jonglei and urges all armed groups to respect the government of South Sudan's appeal to lay down their weapons and to settle their differences by peaceful means," the statement read.
The attack in Jonglei follows a report from the United Nations probing violence that killed at least 85 people in the state in early 2013 when unnamed gangs attacked cattle grazers.
A U.N. report last year said violence between ethnic groups in Jonglei led to deaths, abductions of women and children, destruction of homes and the displacement of thousands of people.
South Sudan became an independent county in 2011 as part of a peace deal that brought an end to Sudan's civil war. Disputes over natural resources, ethnic clashes and border issues have threatened the fragile peace.