Thousands of Yemenis demonstrated in the capital Sanaa on Sunday to vent anger at Riyadh, head of a coalition accused of carrying out air strikes that killed at least 140 people at a funeral.

The protesters gathered outside UN offices in Sanaa and chanted "Death to Al-Saud," the Saudi royal family.

The rally, dubbed the "Volcano of Rage", came a day after bombs hit a funeral ceremony in the capital, in one of the deadliest air strikes since the Saudi-led coalition intervened against Shiite Huthi rebels in Yemen in March 2015.

The attack also wounded more than 525 people, according to the United Nations.

"After this massacre, we are more determined to confront the assailants," prominent rebel chief Mohammed Ali al-Huthi told the crowd. "Open the fronts with the Saudi enemy immediately."

Demonstrators also chanted anti-US slogans coined in Shiite Iran, which backs Yemen's rebels but denies providing military support.

"Allahu Akbar (God is the greatest). America is the Great Satan," they shouted.

The coalition initially denied responsibility for Saturday's strike but later said it was ready to investigate the "regrettable and painful" attack.

The Saudi-led coalition supports Yemen's internationally-recognised government of President Abedrabbo Mansour Hadi against the rebels, who seized the capital and swathes of Yemeni territory in 2014.

The UN says the conflict has killed more than 6,600 people -- almost two-thirds of them civilians -- and displaced at least three million since the Saudi-led intervention.

The coalition has faced repeated criticism from rights groups over civilian casualties in its campaign in Yemen.

Civilians pay highest price in Yemen war
Sanaa (AFP) Oct 9, 2016 - Nineteen months into Yemen's war in which civilians have paid the heaviest price, an air strike has killed over 140 people at a funeral ceremony in the capital Sanaa.

The United Nations says the conflict has killed more than 6,600 people -- almost two-thirds of them civilians -- and displaced at least three million since a Saudi-led Arab coalition backing the internationally recognised Yemeni government launched military operations in March 2015.

UN rights office spokesman Rupert Colville said Tuesday that from March 2015 through September 30, 4,014 civilians had died and nearly 7,000 had been injured.

Casualties climbed steeply in August and September, following the collapse of a ceasefire, with the coalition held responsible for six times as many civilian deaths and injuries as the rebel forces, Colville said.

The coalition said it is ready to investigate together with the United States the air strike Saturday on the funeral ceremony in the capital.

President Abedrabbo Mansour Hadi's government is battling Iran-backed Shiite Huthi rebels and allied forces who have seized control of large parts of Yemen since 2014 and still hold swathes of territory including Sanaa.

The following is a list of alleged human rights violations in the Yemeni conflict and incidents in which civilians have been targeted.

- On August 15, a coalition air strike killed 19 people at a hospital in northern Yemen that is aided by the French charity Doctors Without Borders (MSF). It was the fourth strike on an MSF-backed site in a year, the group says, and raised concern in Washington, which supports the coalition.

The coalition, which says it does not deliberately target civilians, vowed to conduct an internal investigation, as UN chief Ban Ki-moon stressed that attacks on hospitals, medical personnel or civilians were "a serious violation of international humanitarian law".

- On August 4, the coalition acknowledged "shortcomings" in two out of eight cases it had investigated of air strikes on civilian targets. They took place in 2015 and involved a residential complex in Mokha, where 65 people died according to Human Rights Watch (HRW).

- On March 15, air strikes on a market killed at least 119 people, including 106 civilians, of which 24 were children, in the northern rebel-held province of Hajja.

- On September 28, 2015, a suspected coalition air strike killed at least 131 civilians at a wedding near the Red Sea city of Mokha. The Saudi-led alliance denied involvement.