UAE-backed Yemeni government forces seized Hodeidah airport from Houthi rebels on Wednesday, their commander said, in a major step towards retaking the key Red Sea port city.

"The airport was completely cleared, thank God, and is under control," Abdul Salaam al-Shehi, a commander in the Saudi-led coalition battling the Houthi rebels on behalf of the internationally recognised government, said in a video posted by the United Arab Emirates' official WAM news agency.

Clashes have spread to the coastal road leading up to the port, according to a source in the pro-government forces.

In Geneva, coalition spokesman Turki al-Malki confirmed the alliance's gain. "We are now destroying Houthi fortifications near the airport," he said in an interview with Al Arabiya television from Brussels, accusing the Houthis of placing tanks inside residential areas.

'We are now destroying Houthi fortifications near the airport' - Turki al-Malki, coalition spokesman

Hodeidah residents confirmed that clashes around the sprawling airport compound appeared to have abated. However, they said warplanes continued to bombard Houthi positions closer to the city centre, where the rebels have begun to entrench themselves in expectation of fierce street-to-street fighting.

In a televised address, Houthi leader Abdul Malik al-Houthi said fighting would not cease even if the coalition regained the whole country. "The western coast will be a swamp that drowns and finishes the forces of the invaders and the aggressors."

Houthi authorities set up loudspeakers on Hodeidah's main streets playing martial chants and excerpts of Houthi's speeches, another resident said. "The streets have been turned into a big audio stage to boost their fighters' morale.”

The coalition's operation, named "Golden Victory", is being conducted by a number of Yemeni factions and mercenaries on the ground led by Tareq Saleh, nephew of the late former President Ali Abdullah Saleh. They are backed by Emirati troops on the ground and Saudi and UAE warplanes and Apache attack helicopters. Offshore are Saudi and Emirati battleships.

The weeklong assault has left nearly 350 people dead, with sources in Hodeidah hospital telling AFP the airport battle alone killed 156 Houthis and 28 coalition soldiers.

The international community has expressed grave concern over the offensive, which was launched last Wednesday after the UAE secured the support of Yemeni President Abd Rabbuh Mansour Hadi, allegedly against his will.

A displaced Yemeni woman from Hodeida comforts a child in their shelter at a make-shift camp for displaced people in the northern district of Yemen's Hajjah province on 19 June, 2018. (AFP) There are fears that the assault could have grave consequences for the humanitarian situation in Yemen, which with 22 million dependent on aid and 8.4 million on the verge of starvation is already the world's worst, according to the United Nations.

Since 2017, there have been more than one million suspected cases of cholera, with some 2,300 related deaths recorded by the UN.

With the coalition closing in on Hodeidah, a city of 600,000, aid agencies have warned that cholera could spread among the population if water sources are cut off.

"People are saying water has been disrupted in parts of Hodeidah already. Some areas even prior to the war were not even connected to the main water supply," said Saleem Al Shamiri, livelihood coordinator at the Norwegian Refugee Council.

This was confirmed by residents in the embattled city.

"We have been stuck in our houses for five days because we are afraid of going out due to the fighting. Our food supplies will run out within a week and there is no water," Fatima, 56, said, adding that bottled water was very expensive.

Hodeidah's port is the conduit through which as much as 80 percent of Yemen's food, medical and commercial supplies enters the country.

On Tuesday, the UN's World Food Programme hurriedly unloaded three ships full of food aid - enough, it said, to feed six million people for one month.

The coalition has said it intends to quickly secure the port and then avoid pitched battles in Hodeidah city, where some 600,000 people are estimated to live.

"Hodeidah port is operating as normal and the movement of ships is normal," Malki said. "We have humanitarian and development plans for when we liberate the city."

The UN's special envoy to Yemen, Martin Griffiths, was in the country from Saturday to Tuesday seeking an agreement with the Houthis to avoid an all-out assault on the city.

His efforts appeared to have failed, however, as he left the capital Sanaa without any real signs of progress.