Marketplaces in Yemen's rebel-held capital Sanaa were stacked with produce on the eve of the holy month of Ramadan, but there were barely any customers with the means to buy.

Prices have spiked over the course of Yemen's conflict, which since 2015 has pitted a Saudi-led coalition against the Iran-backed Huthi rebels and seen the country's largest port reduced to a wasteland under de facto blockade.

An air strike by the Saudi-led coalition on a primary school in rebel-held northern Yemen on Tuesday killed five people including two children, medical and military sources said.

Yemen's 20-month war has killed more than 7,000 people and wounded nearly 37,000, the World Health Organization said, as the U.N. envoy voiced alarm over the worsening humanitarian situation.

More than 140 people were killed and more than 525 wounded Saturday when air strikes hit a funeral ceremony in Yemen, a United Nations official said, with Huthi rebels blaming the attack on the Saudi-led coalition.

The Saudi-led coalition fighting rebels in Yemen said Sunday it will investigate an air raid that killed more than 140 people, after Washington announced it was reviewing support for the alliance.

A suicide bombing outside a mosque in Yemen's insurgent-held capital killed seven people, rebel media and witnesses said Wednesday.

There was no immediate claim of responsibility but similar attacks have been carried out in the past by the Sunni extremist group Islamic State, which has targeted Shiite Huthi rebels who control Sanaa.

Loyalist forces in Yemen backed by a Saudi-led coalition killed at least 20 Iran-backed insurgents Saturday, the military said, as they pressed their offensive on the rebel-held capital Sanaa.

Twelve other rebels were captured in the operation launched on the northwestern edge of Marib province, a key battleground in the fight for control of the capital, said a military official

A Saudi-led coalition air strike on rebels in a residential area of the Yemeni capital on Tuesday killed at least 21 people including civilians, witnesses and medics said.

The raid targeted Iran-backed Huthi insurgents in the Sabeen neighborhood of the rebel-held capital Sanaa, but nearby homes were also damaged, witnesses said.

Saudi-led warplanes pounded rebel positions in Sanaa on Monday as the rebels called a mass rally to celebrate the first anniversary of their seizure of the Yemeni capital.

Despite six months of coalition air strikes in support of exiled President Abedrabbo Mansour Hadi, expanded into a ground operation in late July, the rebels still control much of the north and center of the country.

Air raids by Saudi-led coalition warplanes killed 15 people in Yemen's capital in one of the heaviest nights of bombardment in months, aid workers and witnesses said Saturday.

One rescuer told AFP at least 10 civilians were among the dead.