Riyadh peace agreement 'legitimises Saudi occupation in Yemen'
The Saudi-brokered power-sharing deal aims to end a north-south rift that has escalated during the country's war.
"The Riyadh agreement between [Abedrabbo] Mansour Hadi's government and the separatist council is incomplete and will not solve the Yemen crisis and its problems," Iran’s foreign ministry said in a statement cited by the official IRNA news agency.
"The Yemeni people will not allow foreign forces to occupy southern Yemen," it added.
Ministry spokesman Abbas Mousavi said the agreement "does not provide any support to solve the problems in Yemen but comes in the context of promoting the Saudi occupation directly or through its forces to the southern part of the country".
Iran has for years been accused of backing Houthi rebels who took over Yemen’s capital city Sanaa in September 2014.
Security Belt Forces - dominated by the STC - in August took control of Aden, which had served as the beleaguered government's base since it was ousted by the Houthi coup.
The clashes between the separatists and government forces, who for years fought on the same side against the Houthis, had raised fears the country could split into two entities.
The STC then expelled internally-displaced Yemenis from the north of the country seeking refuge from the ongoing violence.
"We do believe among those migrating south there are some planted by certain political groups", Mohamed Alsahimi, deputy head of the STC's UK office told The New Arab at the time - accusing some refugees being planted to instigate instability in the country’s south.
The warring factions in recent weeks held indirect talks mediated by Saudi Arabia in the kingdom's western city of Jeddah, which culminated in the deal signed in Riyadh.