Thousands of supporters of Yemen's secessionists have rallied in the southern city of Aden, backing a new group that advocates for autonomy of the country's south.

The group is led by the city's former governor, Aidarous al-Zubaidi. He addressed his supporters on Friday from behind a large bullet-proof glass box, accusing President Abed Rabbo Mansour Hadi's government of failure.

Al-Zubaidi says he will not "remain silent" but can shoulder responsibility in securing and running the south.

A counter-rally in support of Hadi was held in the Khor Maksar district, underscoring Yemen's growing divisions since the outbreak of the civil war in 2015.

Yemen is facing multiple challenges, including the war with Shiite Houthi rebels who control the country's north and a strong al-Qaida presence.