UN Secretary General Antonio Guterres has vowed that Houthi rebels will abide by a peace deal that calls for their withdrawal from Hodeidah, Yemen's government said on Sunday.
Foreign Minister Khalid Al Yamani held talks with Mr Guterres in New York, where the two officials agreed that the rebels must abide by a UN-brokered deal reached in Sweden for a ceasefire in Hodeidah that also calls for armed forces from both sides to withdraw from three key ports and the rest of the province.
This is the first warning from the international body to the rebels and follows reports of numerous Houthi violations of the ceasefire since it went into effect on December 18.
“During our meeting, the Secretary General promised not to let the Yemeni people down," Mr Al Yamani said on Twitter.
He quoted the UN chief as saying the "Hodeidah agreement will be implemented and Houthis will leave the city and ports, this will be the first step towards achieving peace in Yemen".
Mr Al Yamani stressed the need to speed up the implementation of the ceasefire, which is being overseen buy a team of UN monitors led by Patrick Cammaert, a retired Dutch general.
Mr Cammaert arrived in Sanaa, the rebel-held capital, on Sunday after a three-day visit to Saudi Arabia where he accompanied the UN special envoy for Yemen, Martin Griffiths, in meetings with Yemeni government officials including President Abdrabu Mansur Hadi.
The development comes as fighting broke out on Sunday between Houthi fighters and Hajoor tribesmen in north-west Yemen, resulting in dozens of casualties, local journalists said.
The clashes took place in Al Abaiysa in Koushar district, said Abdullah Al Hajoori, a journalist in Koushar.
The Hajoor tribe is the dominant tribe in northern Yemen, led by prominent Salafi figure Sheikh Yahya Al Hajoori.
Sundays clashes were not the first between the Houthis and the Hajoor.
In 2014, before the civil war broke out, the Houthis fought the Hajoor for control of Saada province. Sheikh Hajoori was eventually forced from the province and his prominent Salafi religious centre in Damaj was bombed.
The Houthi rebels went on to seize the capital Sanaa, sparking Yemen’s civil war.
Since then tensions have remained high between Houthis and the Hajoor.
“The Houthi militia has been imposing a strict siege on our areas in Koushar and shell our residences with all kinds of weapons, moreover they bombed the only medical centre in the area and prevent any of the injured fighters of Hajoor tribes to be taken to the centre of the province to be treated,” Al Hajoori said.
“Dozens of fighters from both the tribes and the Houthis were killed amid the fierce clashes raging in the mountainous areas around Koushar.”
On Saturday, nine civilians – including women and children – were killed and 30 injured when a camp for displaced people in Hajjah was shelled. Houthi rebels were believed to be responsible for the attack, said Osama Faraj, a Yemeni army press officer in the province.
"The Houthis shelled the IDPs camp in the early morning using Katyusha rockets," Mr Faraj told The National.
The camp is in a desert area in Bani Al Hadad in Haradh district, he said, about 15 kilometres from the nearest front lines. The camp shelters civilians who fled their homes in Al Shalila following fighting between rebels and pro-government forces last week.
The government body responsible for managing displacement camps in Yemen condemned the incident as a "heinous crime".
"Shelling the camps of the displaced unarmed civilians is a heinous crime, and is considered a war crime," it said.
Around Hodeidah, civilians continue to be caught in the crossfire as clashes threaten the ceasefire in the critical port city. Two civilians were reported killed and five injured by shelling in Haiys district in southern Hodeidah province on Saturday evening. Residents blamed Houthi rebels for the attack.
Despite the ceasefire, Houthi forces continued firing mortars into Hodeidah over the weekend, residents told The National.
In southern Yemen, pro-government Al Amalikah forces reported repulsing a Houthi attack on Al Bareh in Taez province on Saturday.
"This was the biggest attack launched by the Houthi militia over sites controlled by our forces in the southern swathes in the province of Taez in the last couple of months but it was foiled," Al Amalikah spokesman Aseel Al Sakladi told The National.