The US ambassador to the United Nations, Samantha Power, says she is "outraged" that South Sudan's government has harassed civil rights activists who met with a UN Security Council delegation during a visit to the young nation.

Power said in a statement issued Saturday that the delegation observed "chilling" living conditions for civilians trapped in the ongoing conflict between the government and rebel forces. She says the South Sudanese government should elevate, not suppress, the voices of activists "who organize peacefully and provide constructive criticism."

She says the Security Council is "engaging directly with the government of South Sudan to underscore that intimidation and threats toward civil society must cease immediately."

Heads of organizations that met with the diplomats say they have been ordered to report to the government.