Clashes erupted between Houthi rebels and pro-government forces in Yemen's flashpoint port city of Hodeidah on Saturday, dealing a new blow to an already fragile truce.

Artillery and machine-gun exchanges rocked the southern part of Hodeidah in early morning before tapering off later in the day, a correspondent for the AFP news agency said.

The rebel-held port city, which is a lifeline for the delivery of desperately needed humanitarian aid, was for months the main frontline in the Yemeni conflict after pro-government forces supported by Saudi Arabia and its allies launched an offensive to capture it in June.

But last month the warring parties agreed a ceasefire for Hodeidah during UN-sponsored talks in Sweden.

The United Nations has said the truce has largely held since it came into force on 18 December, but there have been delays in the agreed withdrawal of rebel and government forces.

The Houthis control most of Hodeidah while government forces are deployed on its southern and eastern outskirts.

UN aid coordinator Lise Grande visited the city on Friday and met local officials, said Jaber al-Razahi, the head of Yemen's National Authority for the Administration and Coordination of Humanitarian Affairs.

"The reason for the visit of UN humanitarian coordinator Lisa Grande to Hodeidah is to see the humanitarian situation... and ensure the arrival of aid through the port," Razahi said.

Drone control centre 'destroyed'

Also on Friday, the Saudi-led coalition said it had destroyed a communication and control centre used to direct drones deployed by the Houthis, Saudi state TV al-Ekhbariya reported, citing a coalition statement.

Drones belonging to the rebels attacked a Yemeni government military parade in the southern province of Lahaj on Thursday, killing several people.

Since the coalition intervened in support of the government in March 2015, the conflict has killed an estimated 10,000 people and unleashed the world's worst humanitarian crisis, according to the UN

UN aid officials say 80 percent of the population, 24 million people, are in need of aid and nearly 10 million are just one step away from famine, which has already killed some 50,000 Yemenis.