South Sudanese activists say they face government intimidation in retaliation for meeting with the visiting U.N. Security Council last weekend.

At least three local organizations have been told by South Sudan's government they cannot operate. On Wednesday, the U.S. envoy to South Sudan told Congress the number of blacklisted groups could be as high as 40.

One activist says the government harassment is in response to position papers that supported an arms embargo on South Sudan or a new regional protection force. The government dislikes both.

The head of one organization says he was prevented from attending the Security Council meeting.

Government officials were not immediately available for comment Thursday.

The United Nations says it is "deeply concerned."

South Sudan is struggling to recover from civil war.