Two Ugandan journalists were freed in South Sudan on Wednesday after four nights in detention for filming in the capital Juba, the reporters said.

"I am happy I am out and finally to be going back home," said Justin Dralaze, a freelancer, after being released along with his colleague Hillary Ayesiga.

South Sudanese radio reporter Sunday David Tut, who had been helping the Ugandans, as well as their driver, were also arrested but were both also released on Wednesday, Dralaze said.

Ayesiga said they were not mistreated while in custody.

The pair were arrested by security officials on Saturday.

The journalists, who were not expelled but were due to fly home to Uganda later Wednesday, had been reporting for the US-based Feature Story News (FSN) agency.

South Sudan security forces are notoriously heavy-handed and regularly block journalists from filming on the streets of the capital.

Troops and police have beefed up their presence on the streets of Juba after the president sacked all government ministers last week.