The spokesperson of European Union urged the government of South Sudan in Juba to exercise restraint and refrain from further violence.
Catherine Ashton said EU was very concerned about reports of the fighting in Juba from Sunday night to Monday.
She said it was essential to look for peaceful, not military, solutions to political differences.
Ms Ashton added that continued violence will only exacerbate, not resolve the problems.
She called on all parties to protect civilian life, both of South Sudanese and of foreign nationals, and to respect international humanitarian law.