The UN envoy hailed a "constructive" first full day of Yemen peace talks on Friday but called for a halt to air strikes by a Saudi-led coalition and missile fire by Iran-backed rebels.
Ismail Ould Cheikh Ahmed said that firming up a ceasefire that was supposed to have gone into effect on April 11 was essential to the success of the hard-won peace negotiations in Kuwait.
"There should be no air strikes and firing of missiles," the envoy told a press conference.
He said the rebels complained of continuing air strikes by the Saudi-led coalition while the government side complained of continued ceasefire violations by the rebels.
Ould Cheikh Ahmed said he had contacted Saudi Arabia about the coalition air strikes and they had said the raids were ordered only in response to ceasefire violations by the rebels.
"The ceasefire is respected between 70 percent to 80 percent all over Yemen," he said.
"The talks today were very constructive.
"There was a consensus on strengthening the ceasefire and the two sides were committed to the need to achieve peace and that this is the last opportunity."
The negotiations in Kuwait opened on Thursday evening with a session lasting less than two hours following the delayed arrival of representatives of the Shiite Huthi rebels and allied forces loyal to ousted president Ali Abdullah Saleh.
The United Nations hopes negotiations -- which were originally due to begin on Monday -- will put a stop to fighting across Yemen that has killed more than 6,800 people and driven 2.8 million from their homes since March last year.