The southern transitional council (STC) on Monday accused the Islah Party, an offshoot of the Muslim Brotherhood, of seeking to weaken the southerners and the Houthis through igniting battles in south Yemen.
The council's spokesman, Nizar Haitham, said in a statement on Facebook: "Houthi escalation on all warfronts and push into southern borders should be blamed on disloyalties of the Islah Party and its complicity with the Houthis".
"All inside and outside Yemen now know that without betrayal from the Islah Party, and its continued complicity to freeze the anti-Houthi resistance and hand over military camps in the north to the Houthis, the Houthis would not dare to invade our borders".
Yemen has been battered a five-year armed conflict that has created the world's worst humanitarian crisis. The conflict broke out after the Houthis seized the capital Sanaa and ousted the internationally recognised government in late 2014, and escalated after a Saudi-led Arab coalition launched a military campaign to restore the government in March 2015. The Houthis have since been controlling the capital Sanaa and large parts of northern, middle, western and eastern regions.
Last month, they captured the district of Al-Hasha in southern Dhale province and the district of Thi Naem in Bayda province as pushed into the southern provinces of Abyan and Lahj, three years after the pro-government forces with support from the Arab coalition drove them out of the south.
Southern leaders and activists accuse officials in the government of targeting the council through lies and rumors and providing support to the Houthis.
The southern transitional council was established with support the United Arab Emirates, a member of the Arab coalition, in May 2017. It is the umbrella of a number of southern factions calling for the separation of the south from the north.