(AFP) - A heartbroken United Nations chief on Sunday called for the "resurrection" of peace talks between Yemen's warring sides to end the suffering of civilians.

Thousands of people have died in Yemen and millions are struggling to feed themselves almost two years after a Saudi-led coalition intervened to support Yemen's government and halt an advance by rebels.

Seven ceasefires brokered between government and rebel forces by the United Nations have failed, while UN-backed peace talks have repeatedly broken down.

"You know, I am a Catholic. And Catholics believe in resurrection," UN Secretary-General Antonio Guterres told reporters during a visit to the Saudi capital.

"So if negotiations are dead they can always resurrect. And I do believe that they need to for a very simple reason, the suffering of the Yemeni people."

The world body has called repeatedly for a ceasefire to allow the delivery of relief supplies.

UN aid chief Stephen O'Brien warned last month that Yemen could face famine this year if no immediate action is taken.

Guterres, who visited Yemen in his former post as UN High Commissioner for Refugees, praised the generosity of Yemenis despite their poverty.

He said that to see them "suffering so much is something that really breaks my heart".

He spoke at a joint news conference with Saudi Foreign Minister Adel al-Jubeir after talks with King Salman, Crown Prince and Interior Minister Mohammed bin Nayef, and Deputy Crown Prince Mohammed bin Salman, the defence minister.

UN peace envoy Ismail Ould Cheikh Ahmed also attended the press briefing as he continues to push a peace plan that would restore a ceasefire and lead to a political transition in the country.

A Saudi-led coalition of several Arab states began air strikes over Yemen in March 2015 to support the internationally recognised government of President Abedrabbo Mansour Hadi against the Iran-backed Huthi rebels.

The Huthis are allied with former members of the security forces loyal to ex-president Ali Abdullah Saleh.

Late last month, Ould Cheikh Ahmed told the UN Security Council that Hadi, who spends most of his time in Riyadh, "continues to criticise" the peace proposals without agreeing to discuss them.

"And this will hinder and impede the path towards peace," he said.

Under the plan, Hadi's powers would be dramatically reduced in favour of a new vice president who would oversee the formation of an interim government that would lead a transition to elections.

The Saudi foreign minister said blame for the failure of the peace effort lies with the Huthi-Saleh forces.

"We have made more than 70 agreements with Huthi-Saleh and they have not implemented one of these agreements," Jubeir said.

Guterres arrived in Saudi Arabia from Turkey and will be in Dubai on Monday for the World Government Summit during his regional tour.

© Agence France-Presse