The UN Security Council convened Tuesday to discuss the crisis in Yemen, amid growing concern over the deteriorating situation and calls for the parties to re-engage in the political process, diplomats said. The meeting was held behind closed doors, at Britains request. Special envoy for Yemen Martin Griffiths, briefing the council via videoconference, "reiterated the importance of stopping the ongoing military escalation before it is too late," UN spokesman Stephane Dujarric said later. "He warned that recent developments jeopardize the progress the parties had made on de-escalation and confidence building," the spokesman added, according to AFP. One diplomat, speaking on condition of anonymity, said the council would be issuing a statement urging the belligerents to return to the table and expressing its concern over the situation facing civilians. The UN has called it "the worlds worst humanitarian crisis." Earlier in Washington, US Secretary of State Mike Pompeo called on all parties to exercise restraint. "The United States government is alarmed by renewed violence in Yemen," he said in a statement. "Renewed fighting is unacceptable and threatens to undermine this hard-earned progress. "We call on all parties to put the needs of the Yemeni people first and immediately return to restraint. The Houthis must cease attacks on Saudi territory." Clashes between the Iran-backed Houthi militias and legitimate government forces resumed on January 19 after months of relative calm.