The United Nations Yemen mediator urged warring parties on Wednesday to "seize the opportunity" to take decisive steps toward peace and said momentum to end the conflict had been renewed by a deal between Saudi Arabia and Iran to resume ties.

"Intense diplomatic efforts are ongoing at different levels to bring the conflict in Yemen to an end," U.N. special envoy Hans Grundberg told the Security Council. "We are currently witnessing renewed regional diplomatic momentum, as well as a step change in the scope and depth of the discussions."

The conflict in Yemen has widely been seen as a proxy war between Saudi Arabia and Iran. A Saudi-led coalition intervened in Yemen in 2015 after the Iran-aligned Houthis ousted the government from the capital Sanaa in 2014.

Iran and Saudi Arabia announced on Friday that they had agreed to restore diplomatic ties after four days of previously undisclosed talks in Beijing between the Middle East rivals.

"The parties must seize the opportunity presented by this regional and international momentum to take decisive steps towards a more peaceful future," Grundberg, who visited Tehran earlier this week, told the 15-member Security Council.

A U.N.-brokered truce agreed in Yemen last April has largely held despite expiring in October without agreement between the parties to extend it.

"The overall military situation in Yemen continues to be relatively stable ... But this is fragile," Grundberg said.

"The truce can only be a steppingstone. We urgently need to build on what was achieved by the truce and work toward a nationwide ceasefire and an inclusive political settlement to end the conflict in Yemen," he said.