Saudi-backed government forces in Yemen launched a series of attacks on rebel-held Hodeida, military officials said Tuesday, raising fears of a humanitarian crisis as an 11-week pause in the battle for the port city ended.

The Huthi rebels accused the government and its Saudi-led allies of deliberately targeting food warehouses on Monday night, as the coalition said it had resumed a “military operation to liberate Hodeida and its port”.

Pro-government forces and medical sources in Hodeida province told AFP that 40 Huthis had been killed around the port city since Monday night.

The fight for Hodeida, which the Huthis seized in 2014, was put on hold for 11 weeks as the United Nations struggled to bring warring parties to peace talks in Geneva.

But the talks collapsed earlier this month after the northern Yemeni rebels refused to attend.

The Red Sea port of Hodeida is a vital lifeline for aid shipments to Yemen, the most impoverished country in the Arab world.

The United Nations has warned that any major fighting could halt the distribution of food to eight million Yemenis dependent on the supplies to survive.