Yemeni militants loyal to the STC gather with their vehicles as they display the separatist flag. AFP
The separatist Southern Transitional Council is part of Yemen's internationally recognised government, a patchwork of groups held together by their opposition to the Houthis, which rule much of the country's north.
This month, the STC swept through swathes of the country, expelling other government forces and their allies in a move that sparked fears of secession and further instability.
"The Kingdom of Saudi Arabia points out that the military movements in the governorates of (Hadramawt and Al-Mahra), recently conducted by the Southern Transitional Council, were carried out unilaterally, and without the approval of the Presidential Leadership Council (PLC) nor in coordination with the Coalition's leadership," the Saudi foreign ministry said in a statement.
"These movements resulted in an unjustified escalation that harmed the interests of the Yemeni people with all of its segments," it added.
"The Kingdom remains hopeful that the public interest will prevail through ending the escalation by the Southern Transitional Council and the withdrawal of its forces from the two governorate in an urgent and orderly manner," it added.
A Saudi-Emirati military delegation visited Aden for talks earlier this month to ask the STC to return the two provinces it recently seized, the statement said, adding that Saudi efforts for de-escalation were ongoing.
A source close to the STC had told AFP at the time that the delegation asked them to withdraw from the newly-seized territory but that the group refused.
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