The U.N. special envoy to Yemen sought to downplay the significance of the failure of peace talks to start, saying on Saturday that he would head back to Yemen "within days" to try and agree on a new date.

A delegation of the internationally recognized government arrived in Geneva for the talks, which were supposed to start Thursday, but their war rivals — Iranian-backed rebels known as the Houthis — did not, arguing they could not go because they did not have guarantees for their safe return.

Addressing a news conference in Geneva, Martin Griffiths declined to blame either side for the failure to start the talks, saying apportioning blame would not help Yemen. He insisted that the "consultation" — the term used by the U.N. to refer to the talks — had begun when he and his team held three days of talks with the government delegation.

"There was an effort on the part of the Ansar Allah to come here," said Griffiths, using the formal name of the Houthis. "They wanted to be here. We just did not make it. It's not the first time that we have difficulties in a Yemeni context. Criticizing one or the other doesn't help Yemen. Things happen."

The envoy's refusal to apportion blame angered the Yemeni government. Addressing a news conference that immediately followed Griffith's, Yemen Foreign Minister Khaled al-Yamani said the envoy's comments sought to "appease and find excuses" for the Houthis. Their failure to travel to Geneva, he added, showcased their "irresponsibility."

The talks would have been the first between Yemen's war rivals in two years.

The Houthis insist on traveling to Geneva on an Omani flight, saying that would ensure their safe return to Yemen. "We want guarantees on our return to Yemen," senior Houthi official Deif Allah al-Shami said Friday.

On Thursday, senior rebel official Mohammed Ali al-Houthi said on Twitter that the Saudi-led coalition backing Yemen's internationally recognized government refused to grant the Omani flight authorization to transfer their delegation to Geneva. He said that raised the risk of being prevented from returning to Yemen, which he said happened in 2016 after a failed round of talks.

The coalition, which has imposed a land, sea and air blockade on Yemen since 2016, denied the allegation.

Yemen has been locked in a ruinous war pitting the Saudi-led coalition backing the government of Abed Rabbo Mansour Hadi against the Houthis since March 2015. Saudi-led airstrikes have hit schools, hospitals and wedding parties and killed thousands of Yemeni civilians. The Houthis have fired long-range missiles into Saudi Arabia and targeted vessels in the Red Sea.

At least 10,000 people have been killed in Yemen's conflict, which has exacerbated what the U.N. calls the world's worst humanitarian crisis.