Sporadic clashes broke out on the outskirts of Yemen's Hodeidah on Friday, the first violence to hit the lifeline port city since a United Nations-brokered ceasefire was reached by warring parties, residents said. 

Residents reported hearing sounds of exchange of gunfire and missiles in the Houthi-held city, on whose outskirts Yemeni forces backed by a Saudi-UAE coalition have massed.

The clashes in Hodeidah, a lifeline for millions of Yemenis facing starvation, came a day after the Houthis and the Saudi-backed government had agreed after a week of consultations in Sweden to cease fighting in the Red Sea city and withdraw their troops.

It was the first significant breakthrough for the UN-led peace efforts to pave the way for political negotiations to end the nearly four-year-old war that has killed tens of thousands of people and pushed Yemen to the brink of famine.

'Daunting task'

UN Special Envoy for Yemen Martin Griffiths said at the end of the Sweden peace talks that both parties would withdraw "within days" from the port, and subsequently from the city.

International monitors would be deployed and all armed forces would pull back completely within 21 days and a prisoner swap involving some 16,000 inmates is planned.

On Friday, Griffiths told the UN Security Council that a robust monitoring regime was urgently needed in Hodeidah to oversee compliance with the truce.

Al Jazeera's James Bays, reporting from the UN headquarters in New York, said the organisation is "trying to come up with a monitoring team" for Hodeidah. He added that the UN's task ahead is "a very, very difficult" and "daunting" one. 

Yemen, the Arab world's poorest country, has been devastated by a multi-sided conflict involving local, regional and international actors.

The conflict in Yemen began with the 2014 takeover of the capital, Sanaa, by Houthi rebels, who toppled the government of Abed Rabbo Mansour Hadi. A Saudi-UAE-led coalition allied with Yemen's internationally recognised government has been fighting the Houthis since 2015.

Since then, more than 60,000 people have died, according to rights groups, and now the country is on the brink of a famine.