The raids came as firefights on the eastern and southern edges of the rebel-held city killed 26 insurgents in the past 24 hours, the officials and doctors in two different hospitals said.

Five pro-government fighters were killed in the clashes with the Iran-aligned rebels and by landmines, the officials told AFP.

The air strikes targeted convoys of rebel reinforcements at the northern entrance to Hodeida and south of the city, they said.

The renewed violence came after UN envoy Martin Griffiths visited Hodeida on Friday to assess the humanitarian situation ahead of peace talks planned for December between Yemen's coalition-backed government and the rebels.

Rebel spokesman Mohammed Abdessalam said on Twitter there had been "35 air raids over the last 12 hours on Hodeida, accompanied by artillery bombardments".

"This escalation destroys the efforts of the UN envoy", he said.

Under heavy international pressure, the Yemeni government and the coalition had until Sunday largely suspended a five-month offensive against the port city.

Fighting had intensified in early November as Yemeni forces backed by the coalition attempted to enter Hodeida, but calm returned after Griffiths arrived in Yemen on Wednesday.

After visiting Hodeida on Friday, Griffiths on Saturday met Mohammed Ali al-Huthi, head of the rebels' Higher Revolutionary Committee, in the insurgent-held capital Sanaa.

The rebel leader on Sunday described the renewed air raids and other hostilities in Hodeida as "an insult" to the UN envoy.

Griffiths is due to hold talks with Yemen's internationally recognised government in the Saudi capital Riyadh on Monday, according to a UN source.

UN agencies say up to 14 million Yemenis are at risk of starvation if fighting closes the city's port, from which nearly all imports and humanitarian aid pass.

According to UN figures, nearly 10,000 people have been killed since the coalition joined the conflict in 2015 to reinforce the government, triggering what the UN calls the world's worst humanitarian crisis.

Rights groups fear the actual toll is far higher.