RIYADH (Reuters) - Yemen’s southern separatist movement called on Wednesday for an uprising in the restive port city of Aden and the southern provinces against the country’s internationally-recognized government.

FILE PHOTO: Aidaroos al-Zubaidi, leader of Yemen’s Southern Resistance, poses for a picture during Reuters interview at the headquarters of the Southern Transitional Council in Abu Dhabi, United Arab Emirates September 19, 2018. REUTERS/ Aziz El Yaakoubi

The call could put further pressure on U.N. Special Envoy Martin Griffiths, who is expected in Abu Dhabi later on Wednesday to meet Emirati officials and Aidaroos al-Zubaidi, who is president of the Southern Transitional Council (STC) and leader of the separatist movement.

Tensions between southern separatists, backed by the United Arab Emirates, and the Saudi-based government of President Abd-Rabbu Mansour Hadi demonstrate the complexity of Yemen’s war, as both sides are also allied against the Houthi group which controls the capital Sanaa.

The separatists want to revive the former South Yemen republic which merged with the north in 1990.

“We assure our people in all the southern provinces that we support a popular uprising which would end the suffering, and we insist that it be peaceful,” the STC said in a statement.

It called on “the people to control the government’s institutions that provide revenues” but did not say whether this should include oilfields.

Yemen is a small oil producer, with proven reserves of around 3 billion barrels, according to the U.S. Energy Information Administration (EIA). Yemen produced about 500,000 bpd before the war, with more than half of it coming from the Hadramout region in the south.

PROTESTS

The STC statement also urged the separatist forces to protect southern Yemenis protesting against the deteriorating economic situation and a weakening currency.

The Southern Resistance forces, which have been built and armed by the UAE, have more than 50,000 fighters, including 20,000 armed men battling the Iran-aligned Houthi movement in the port city of Hodeidah.

Violent protests rocked Aden and other southern provinces last month after separatist officials issued similar calls.

The southern Yemenis, the government of President Hadi and the Houthis have all been blaming each other for the collapse of the Yemeni riyal and using the central bank to score political points to gain more allies.

The United Nations has renewed efforts to end Yemen’s nearly four-year war with a plan that calls on the Houthis and Hadi’s government to agree a peace deal under a transitional governing body.

Announcing Special Envoy Griffiths’ trip to Abu Dhabi, his office said he was working on confidence-building measures, without elaborating.

The Southerners have been providing the bulk of a ground force led by the UAE that is trying to capture Hodeidah, Yemen’s main port city, from the Houthis. They have urged the U.N. to include the issue of the south’s possible secession from Yemen in the peace talks.

In an interview with Reuters last month, Zubaidi dismissed suggestions that he was putting pressure on the U.N. envoy over the peace talks, but he said they should include the southern separatists because they control the ground.

Yemen has been caught up in a proxy-war between Saudi Arabia and its arch-rival Iran, which has killed more than 10,000 people, displaced millions and pushed the impoverished country to the verge of starvation.