Earlier in the day, fighting between the STC and government forces broke out to the east of the city of Zinjibar, the capital of the southwestern Abyan province. A military source said that the Yemeni armed forces had tried to cross the line of contact and impose control on the city.
"Today, we have witnessed an escalation of a military campaign which brings us back to the past wars of conquest against the south in 1994 and 2015 by the armed groups of the Houthis and the Muslim Brotherhood* who have deployed their forces to the south", Zubaidi said in a statement.
He has issued a call to defend southern Yemen from an invasion.
"We are defending the people's wishes in the south as well as their choice of independence, restoring and building a modern, federative, and completely independent country", Zubaidi added.
In November 2019, the internationally recognized government of Yemen, led by President Abd Rabbuh Mansour Hadi, and separatists operating in the south of the country signed a peace treaty in the Saudi Arabian capital of Riyadh.
The STC was created in 2017. The secessionist movement is backed by the United Arab Emirates, which is part of a Saudi-led coalition that has launched an air campaign against the Houthi rebels in Yemen.
* The Muslim Brotherhood is a terrorist organization banned in Russia