United Nations (UN) Secretary-General Antonio Guterres urged all parties in Yemen to cease hostilities and pledged that the UN will continue to support them in implementing agreements signed since 2018.

"I urge all parties to cease hostilities. The United Nations will continue to support them in implementing these agreements," the UN chief told the High-level Meeting on Yemen on Thursday, which aims to mobilize international support for a nationwide ceasefire in Yemen as well as economic and humanitarian measures, Xinhua news agency reported.

"Since 2018, Yemeni parties have reached a series of agreements, namely the UN-brokered Stockholm Agreement and the Saudi-facilitated Riyadh Agreement, which, if implemented, would lay the groundwork for sustainable peace. We must build on these important milestones," said the secretary-general.

"More than five years of war have devastated the lives of tens of millions of Yemenis, brought state institutions to the verge of collapse and reversed development by decades," Guterres said.

"With the coronavirus pandemic, the urgency of reaching a negotiated political settlement to end the conflict has only grown," he added.

Speaking of the impact of the COVID-19 pandemic, the UN chief said that there are more than 2,000 confirmed cases of COVID-19 in Yemen. "But experts estimate that there are possibly up to 1 million affected by the virus, with a fatality rate as high as 30 percent, as war has decimated the country's health facilities."

On the conflict situation, Guterres noted that the conflict continues unabated, "despite initial expressions of support by the warring parties for my call for a global ceasefire and a Yemeni-specific truce."

"In recent weeks, conflict has unfortunately escalated," he added.

He said airstrikes and ground clashes result in many civilian casualties, and Houthi drone and missile attacks on the Kingdom of Saudi Arabia persist.

"More civilians were killed in August than any other month of the year, with one in four civilian victims killed and injured in their own homes," he said.

"I call again on all parties to cooperate under the facilitation of my special envoy and engage in good faith, without preconditions, in efforts to reach an agreement on the Joint Declaration, comprised of a nationwide ceasefire, economic and humanitarian confidence-building measures, and the resumption of the political process," the UN chief said.

He also expressed deep concern over the SAFER oil tanker, moored off the western coast of Yemen.

"Since 2015, it has had almost no maintenance. An oil spill, explosion or fire would have catastrophic humanitarian and environmental consequences for Yemen and the entire region," he said.

Talking about the high-level pledging conference on June 2, Guterres said all donors should fulfill the pledges made at the conference and increase their support.

"Donors at the June 2 event pledged only half as much as the year before, so it is very worrying that meaningful sums still remain unpaid," he said.

He added that only 30 per cent of the UN response plan is funded, noting that the fulfillment of the pledges is vital to prevent a devastating famine.

"Now is the time to step up for the people of Yemen," the UN chief said.