The UN must assert pressure on Yemen’s Houthi rebels to stop their attack on Marib because millions of lives are at risk, the government said on Monday. The Iran-backed rebels have been pushing on several fronts towards the last government-controlled major city in the north. “Yemen’s Foreign Minister, Mohammed Al Hadrami, stressed the need for the UN Security Council to assume its responsibilities and condemn the ongoing escalation and Houthi violations in Marib governorate,” his ministry said. Mr Al Hadrami condemned Houthi attacks on residential areas in the governorate, especially with ballistic missiles and drones. “This indicates that the Hodeidah ceasefire, brokered by the UN in Stockholm in 2018, has become useless and the Houthis exploitation is unacceptable and cannot continue,” the ministry said. The comments came as Mr Al Hadrami met the UN envoy to Yemen, Martin Griffiths, in Saudi Arabia. Yemen's leaders have lived in Riyadh since the rebels overran the capital, Sanaa, in 2014 and pushed out the government. Mr Griffiths ended his round of talks with Yemeni and Saudi officials on Sunday night, where he discussed the “dire humanitarian consequences of the military escalation in and around Marib", his office said. “Marib continues to be a safe haven for hundreds of thousands of internally displaced Yemenis." Mr Griffiths said the attack on Marib must immediately cease. Yemen's Parliamentary Speaker, Sultan Al Burkani, said the UN must take “serious steps towards achieving just and comprehensive peace". Mr Al Burkani said that Yemen “can no longer tolerate more leniency towards the Houthis or silence from the UN and international community". “Peace efforts are being confronted by the Houthis' escalation in Marib,” he said. The UN envoy has been pushing both sides to agree on a process to end the civil war. Mr Griffiths' proposal calls for a nationwide ceasefire, including all air, ground and naval hostilities. It also calls for the parties to ensure compliance on the front lines between government forces and the rebels. But lack of trust between the two sides has slowed the UN's push for peace.