Southern Transitional Council (STC) secretary general Abdulrahman al-Subaihi read a prepared statement on a Saudi TV news channel.
"We announce the dissolution of the Southern Transitional Council," read the statement, which was also carried by the Saudi-backed Yemeni government's official news agency.
It also pledged their "commitment to working towards achieving our just southern goal through preparations for a comprehensive southern conference under the auspices of the Kingdom of Saudi Arabia".
Subaihi is among a 50-plus STC delegation that has been incommunicado since arriving in Riyadh in the early hours of Wednesday.
The delegation was summoned to Riyadh after the United Arab Emirates-backed STC seized swathes of territory last month before being repelled by Saudi warplanes and pro-Saudi forces.
However, STC spokesman Anwar al-Tamimi, who is in Abu Dhabi, rejected the announcement coming out of Saudi Arabia.
"This news is ridiculous," he told AFP, confirming the delegation remained out of contact.
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