The chief negotiator of the SPLM in Opposition has called for an end to fighting in former Western Equatoria and Bahr el Ghazal states.
Taban Deng Gai alleges that government forces attacked their bases in Mundri early this week, an incident he described as violation of the peace agreement.
But the government has denied attacking the opposition.
In a previous statement to Eye Radio, the Governor of Amadi State said those who caused the fighting were suspected criminals. He said some of them were arrested.
Mr Taban Deng says there is no need for further fighting.
“Let’s stop it. It doesn’t serve anybody,” told reporters, after a meeting with civil society activists.
Eye Radio’s efforts to contact the minister of information, Michael Makuei Lueth have been unsuccessful.
But Presidential press secretary Ateny Wek Ateny says the SPLM in Opposition has no bases in the former Western Equatoria State.
“Comrade Taban should not claim that SPLM-IO is having cantonment in those areas,” Mr Ateny said.
The ceasefire is among key provisions of the peace agreement.
All the parties to the deal are now expected to finalize security arrangements for Juba and form a government of national unity.