Five civilians including a child were killed Sunday when their house was bombarded near Yemen's strategic Red Sea port of Hodeida, the latest violence in the grinding civil war.

The Saudi-backed government and Huthi rebels traded blame for the devastating attack near frontlines south of the Huthi-held port.

"Five civilians, including a woman and a child, were killed in a mortar bomb strike on their residence by the Huthis," a government military official told AFP.

But the Iran-backed Huthis, according to the rebel-run Saba news agency, said the explosion was caused by two air strikes by the Saudi-led coalition, which intervened in the war in 2015 to back the internationally recognised government.

Hodeida, which lies some 145 kilometres (90 miles) southwest of the rebel-held capital Sanaa, is a lifeline gateway for food, fuel and humanitarian aid.

The United Nations last month warned that thousands of Yemeni civilians were at risk in the western Hodeida province after fighting escalated.

Last month Huthi fighters fought with pro-government forces south of the port in some of heaviest clashes since a UN-negotiated truce in 2018.

The violence comes amid heavy fighting in the Marib region, some 120 kilometres (75 miles) east Sanaa, as Huthi forces seek to wrest control of the government's last northern stronghold.

The Huthis have also stepped up drone and missile strikes on Saudi Arabia, including a thwarted missile attack on Riyadh on Saturday, the kingdom said.

Yemen's conflict has claimed tens of thousands of lives and displaced millions, according to international organisations, sparking what the UN calls the world's worst humanitarian crisis.

Meanwhile, Yemen's Iran-backed Huthi rebels claimed Sunday the attempted strikes that targeted the Saudi Arabian capital Riyadh and other regions overnight, threatening more attacks.

"The operation was carried out with a ballistic missile and 15 drones... targeting sensitive areas in the enemy's capital of Riyadh," said Huthi spokesman Yahya al-Saree, according to the rebels' Al-Masirah TV channel.

"Our operations will continue and will expand as long as the aggression and seige on our country continues."

A Saudi-led military coalition -- which has been backing the Yemeni government against the rebels since 2015 -- said Saturday it thwarted a Huthi ballistic missile that targeted Riyadh.

Fragments of the missile scattered over several Riyadh neighbourhoods, damaging at least one home but no casualties were reported, Saudi's state-run Al-Ekhbariya television said.

Separately, the coalition said it had intercepted six Huthi drones targeting the kingdom, including the southern cities of Khamis Mushait and Jizan.

Saree on Sunday claimed those attacks as well, warning residents in the region to "stay clear from all military airports and sites".

The Huthis have escalated attacks on the kingdom, while they step up an offensive to seize the Yemeni government's last northern stronghold of Marib.

Years of bombings have failed to shake the rebels' hold on Yemen's capital Sanaa, and they have steadily expanded their reach in the country's north.

Yemen's grinding conflict has claimed tens of thousands of lives and displaced millions, according to international organisations, sparking what the UN calls the world's worst humanitarian crisis.