Sanaa, Apr 28 (IANS): UN Special Envoy for Yemen, Martin Griffiths, expressed concerns over the declaration of self-rule by the Southern Transitional Council (STC) in the port city of Aden, breaking a peace deal signed last November with the internationally recognised government.

"Now, more than ever, all political actors must cooperate in good faith, refrain from taking escalation actions, and put the interests of Yemenis first," Griffiths said in a statement on Monday.

He called for "expediting the implementation of the Riyadh Agreement, with the support of the coalition led by Saudi Arabia", reports Xinhua news agency.

"The Riyadh Agreement provides for the participation of the STC in consultations on the final political solution to end the conflict in Yemen and serve the interests of Yemenis nation-wide," Griffiths stressed.

On Sunday, the STC declared establishing a self-ruled administration and a state of emergency in Aden and southern provinces.

The Saudi-led coalition called on the STC to cancel its "escalating move" and abide by the Riyadh Agreement.

The agreement was reached between the STC and the Yemeni government last year, ending months of stand-off between both sides in Aden.

As part of the Arab military coalition that intervened in Yemen in March 2015 to restore power to the government of Yemeni President Abd-Rabbu Mansour Hadi, the STC turned against the Yemeni government last August.