The Security Council failed to agree Wednesday on a statement supporting the U.N. special envoy to Yemen who is trying to get Shiite rebels to back a peace deal and end the 17-month civil war in the Arab world's poorest country.

Yemen's internationally recognized government has approved the U.N.-proposed deal but Houthi rebels have so far rejected it.

Russia's U.N. Ambassador Vitaly Churkin told reporters "the council was almost ready to make a joint pronouncement in support of the political process" when a delegation made an unacceptable demand.

Diplomats said Britain and other council members wanted a statement to criticize the Houthis for announcing a formal alliance with the country's ousted president and his former ruling party by setting up a new political council to rule the country, a step U.N. envoy Ismael Ould Cheikh Ahmed described as jeopardizing peace efforts.

Britain's deputy ambassador Peter Wilson, clearly referring to Russia, said one country wasn't supporting its own national position.

Diplomats pointed to a statement issued by ambassadors in Yemen, including the Russian envoy, which noted "with concern" the July 28 announcement by the Houthis on the political council.

The diplomats, speaking on condition of anonymity because the council meeting was closed, said Cheikh Ahmed wanted the council to express concern about the Houthis' action, urge all parties to abide by a cessation of hostilities that has been repeatedly broken, and call for flexibility in the peace talks — but Russia wouldn't accept any criticism of the Houthis.

U.S. Ambassador Samantha Power said the need for a peace agreement "is acute" and warned that if the U.N.-sponsored talks in Kuwait fail "the risks would be grave."

The Houthis and forces allied to ousted President Ali Abdullah Saleh seized the capital Sanaa in September 2014, forcing the internationally recognized government to flee the country. A Saudi-led coalition has conducted an extensive air campaign against the Houthis since March 2015, pushing them out of southern Yemen, but failing so far to dislodge them from the capital Sanaa and the rest of the north. Meanwhile, extremist groups including the Islamic State and Al Qaida in the Arabian Peninsula have exploited the turmoil and expanded in the south.

Power said the crisis has resulted in thousands of casualties and more than 21 million Yemenis need humanitarian assistance.

Russia's Churkin described Yemen as "a forgotten war," overshadowed by other conflicts in the region but causing comparable suffering and enormous humanitarian costs.

Churkin said Russia and others were under a misunderstanding that the proposed deal only dealt with military issues, and a political agreement was missing.

The deal being negotiated would force the Houthis to hand over their weapons and withdraw from the cities within 45 days of signing the agreement.

But Churkin said Cheikh Ahmed reassured the council in Wednesday's closed briefing "that his idea is to work towards a comprehensive settlement, and that so far he has not made the political part of the package public."

"So now I come away a little bit reassured that we continue to be on track towards a political settlement," Churkin said.

U.N. deputy spokesman Farhan Haq said Cheikh Ahmed plans to hold intensive talks in the coming days to try to get the Houthis to support the peace deal.

Malaysia's U.N. Ambassador Ramlan Bin Ibrahim, the current council president, expressed hope "the council will be able to find consensus on the way forward."