South Sudan's security services have detained two Ugandan journalists who were filming in the capital Juba, officials said on Monday.

Justin Dralaze and Hilary Ayesiga, both freelancers, were arrested by security officials on Saturday.

"They were arrested by the national security services, yes," Cleophas Muhatana, the security attache at the Ugandan embassy in Juba, told AFP.

"We have been in touch with the directorate of national security and they said they are still interrogating them and they will be in touch with us," Muhatana said.

Mustafa Biong, a senior official at the South Sudanese information ministry, confirmed the arrests.

Oliver Modi, who heads the Union of Journalists of South Sudan (UJOSS), said relations between the security services and the media have deteriorated recently.

Three South Sudanese journalists were detained briefly last week, one in Juba and two in the northern oil-rich state of Unity.