Ambassadors of the 10 countries sponsoring the Gulf Cooperation Council initiative (GCC) in Yemen welcomed a deal signed between the Yemeni government and Shiite Houthi rebels.
In a letter, the 10 nations urge all political parties and other groups to implement the deal.
Under the deal, a new government will be formed and the Houthis and southern separatists will nominate a new prime minister within three days.
It comes hours after the prime minister quit amid clashes between rebels and pro-government forces in the capital.
Scores of people have died and hundreds fled as clashes escalated in Sanaa.