Saudi-led coalition, that has carried out strikes in Yemen since 2015, does not back the call for secession.
Senior tribal, military and political leaders in Yemen have formed a new council that seeks the secession of southern Yemen, one week after mass protests in the streets of Aden, according to the former governor of Aden Aidaroos al-Zubaidi.
Al-Zubaidi made his announcement in a televised address in front of the flag of the former nation of South Yemen, whose forces were defeated by the north in 1994 and brought into a reunified country.
He said the new body would continue to cooperate with the coalition and foreign powers to combat what he called Iranian influence and terrorism.
But Saudi Arabia and its key ally the United Arab Emirates, despite arming and funding southern troops during the war, do not back secession and say they fight for a unified Yemen. The southern part of Yemen has most of the country's oil.
Many southerners feel that officials in the north have exploited their resources and cut them off from jobs and influence.
War broke out two years ago between forces aligned to the Saudi-backed government of President Abdrabbuh Mansour Hadi and Iran-backed Houthi rebels. Large parts of the country are now under the control of the rebel forces. More than 10,000 people have been killed in the conflict so far.
The new announcement will likely worsen the division, as it effectively is trying to re-establish the former Southern Yemen state with Aden as the capital.
Cholera puts millions of Yemenis at risk
An outbreak of cholera has killed at least 51 people in Yemen during the past two weeks. The World Health Organisation said there are 2,752 suspected cholera cases and 58 more people have been confirmed as having the diarrheal disease.
Cholera is caused by ingesting contaminated food or water. It can kill within hours if left untreated. The United Nations says at least two-thirds of the population in Yemen have no access to safe drinking water.
Outbreaks in the country are frequent - but made worse by two years of civil war which has devastated Yemen's health and sanitary system.
The capital Sanaa was worst hit, with 34.6 percent of the cases, followed by the surrounding province with 12 percent, the data showed. Cases were also reported in Yemen's other major cities: Hodeidah, Hajjah, Ibb, Taiz and Aden.
WHO said that 7.6 million people live in areas at high risk of cholera transmission.
Although most sufferers have no symptoms or mild symptoms that can be treated with oral rehydration solution, in more severe cases the disease can kill within hours if not treated with intravenous fluids and antibiotics.