Martin Griffiths, the UN special envoy to Yemen, insisted on Wednesday that a three-week-long ceasefire in Hodeidah was largely holding up but hinted that new peace talks may be delayed.
Mr Griffiths told the UN Security Council that both Yemen's internationally-recognised government and the leader of the country's Houthi rebels had assured him in recent days that they remain committed to the truce, despite reports of clashes in the Red Sea port city.
But although violence has fallen markedly in Hodeidah the war is continuing across the country and more has to be done before further negotiations take place, the UN envoy said in a briefing.
"Both sides have largely adhered to the ceasefire and there has been a significant decrease in hostilities," Mr Griffiths said of the agreement which came into force on December 18, a week after a first round of peace talks took place in Sweden.
"Unfortunately, there has been some violence, including in Hodeidah city and in the southern districts of the governorate. However, the violence is very limited to what we saw in the weeks before the Stockholm consultations," he added, speaking to the Council from Amman via video link.
Although a small advance team of United Nations observers, thought to number around a dozen, are in Hodeidah to monitor the ceasefire the UN Secretary-General Antonio Guterres is said to want this number to rise to 75. A new Security Council resolution is being prepared to make that happen.
Mr Griffiths said that while the Hodeidah ceasefire had made a tangible difference its practicalities were still being worked on by Patrick Cammaert, the former Dutch General appointed by the UN to enforce the truce, who arrived in Yemen on December 22.
"He is working with the parties on the details of the redeployments of forces, provision of security in the city and the opening of humanitarian access routes agreed in Stockholm," Mr Griffiths said of Mr Cammaert.
The sporadic violence still affecting Hodeidah has put pressure on the UN over whether the peace process can produce a lasting income to the war that broke out between Yemen's government and the Houthis in 2015. Kuwait has been mooted as a venue for a second round of talks to take place early this year.
But Mr Griffiths appeared to be cautious about such a timeline.
"There is a lot of work that needs to be done before the parties can reach a comprehensive peace agreement," he said. "We need to convene the next round but we need substantive progress on what was agreed in Stockholm.
"Otherwise the next round will only be a forum to discuss achievements of round one," he said of new negotiations.
Mr Griffiths met Yemeni Prime Minister Abdrabu Mansur Hadi in Riyadh on Tuesday, having earlier travelled to Sanaa for talks with rebel leader Abdelmalik Al-Houthi.
"They have both expressed their determination to find a way forward on all of their commitments, and to build further on the progress made through a subsequent round of consultations," Mr Griffiths told the Council.
Yemen's government, however, has accused the Houthis of endangering the deal. Yemen's Foreign Minister, Khalid Al Yamani, said Houthi rebels are continuing to consolidate their forces in the port city in violation of the agreement.
UAE Minister of State for Foreign Affairs Dr Anwar Gargash on Wednesday urged the UN to take a firm stance against the Houthis over the ceasefire. "The Security Council meeting today is vital, the UN must be clear and firm towards the Houthis commitment to withdraw from Hodeidah," he wrote on Twitter.
Following Mr Griffiths' comments to the Council, he received support from Britain and France over his efforts to curtail the fighting in Yemen and bring an end to the war.
The ceasefire is regarded as the most significant step towards ending the conflict that has created a humanitarian crisis where two-thirds of the population is dependent on humanitarian aid.
The Stockholm agreement stipulates that armed forces from both sides must withdraw Hodeidah's three ports, the entry point for most of the aid and food shipped to Yemen, followed by a withdrawal from the city and the rest of the province. Local forces will then take control of the city and ports, but they will remain under UN supervision.
UN officials have said there has not yet been a substantial improvement in the humanitarian situation. On Wednesday, Mark Lowcock, the UN's emergency relief coordinator, said Yemeni civilians were "a little more confident and a little less afraid that they will be victims of air strikes or caught in crossfire as they go about their lives" but it was "very early days" on the road towards peace.
"I cannot yet report to you that the wider humanitarian situation in Yemen is any better. It remains catastrophic," he told the Security Council.