NAIROBI, Kenya (AP) — The U.S. news organization National Public Radio says that one of its journalists has been released by South Sudan's government which held him for nearly four days.

Isabel Lara, a spokeswoman for NPR, told The Associated Press that reporter Eyder Peralta was held for three nights and released on Monday. Peralta has returned to his base in Kenya.

The spokeswoman said that Peralta's South Sudanese assistant is still being held by authorities.

South Sudan officials did not respond for requests for comment.

Peralta's detention was the latest in a crackdown on foreign journalists in South Sudan, the East African nation which gained independence in 2011 but has experienced renewed civil war.