ADEN (Reuters) – An U.N. monitoring mission on Monday called on Yemen’s warring parties to hold new talks over Hodeidah as the Saudi-led coalition strafed areas south of the port city, where Houthi fighters advanced in the wake of withdrawing coalition forces.

The air strikes, which began on Sunday, were the first since late 2018 when the Saudi-backed government and the Iran-aligned Houthis agreed a U.N.-sponsored pact for a truce in Hodeidah and a troop redeployment by both sides that never materialised.

Coalition spokesman General Turki al-Malki, in the first clarification on the abrupt withdrawal from around Houthi-held Hodeidah City, said the redeployment was ordered to support other fronts and in line with the coalition’s “future plans”.

The U.N. mission overseeing the Hodeidah deal, UNMHA, and the Yemeni government team involved in it had said they had no advance notice, while some Yemeni coalition units have criticised the withdrawal, including Red Sea coast fighters.

UNMHA on Monday said the departure of joint Yemeni forces from Hodeidah city, al-Durayhimi, Bayt al Faqih and parts of al-Tahita and subsequent Houthi takeover was “a major shift” in frontlines that warranted discussions between the parties.

The coalition earlier said it carried out 11 air strikes “outside the areas covered under the Stockholm pact”.

Houthi fighters on Monday clashed with Yemeni coalition forces in Hays district, south of Hodeidah city, two military sources said, following fighting in Al Faza on Sunday.

The United Nations said the shifting frontlines led some 700 families to leave for Al-Khokhah and some 180 families head further south to Al-Mokha, both under coalition control.

It was not clear if the Hodeidah pullback was linked to what the coalition has described as a redeployment in the south, where sources said the Saudi military had left a main base in Aden, the interim seat of government.

Yemen has been mired in violence since the Houthis ousted the internationally recognised government from the capital, Sanaa, in late 2014, prompting the coalition to intervene in a conflict seen as a proxy war between Saudi Arabia and Iran.

U.N. and U.S. efforts to engineer a nationwide ceasefire have stalled as the Houthis insist the coalition first lift a blockade on their areas, while Riyadh wants a simultaneous deal.

(Reporting by Mohammed Ghobari; Additional reporting by Nayera Abdallah; Writing by Ghaida Ghantous Editing by Angus MacSwan and Mark Potter)