Sanaa, Jun 13 (IANS): Saudi-backed government forces on Wednesday began an assault on the key Yemeni port of Hudaydah, which is held by Iranian-backed Houthi rebels.

The bombing started after the rebels ignored a deadline set by the government of President Abdrabbuh Mansour Hadi to withdraw by Tuesday midnight, the BBC reported.

The "liberation" of Hudaydah began with a large-scale ground assault supported by air and naval cover from a Saudi-led multinational coalition.

Coalition warplanes and warships carried out strikes against rebel positions around the city, the BBC reported citing Saudi's Al Arabiya network.

"The liberation of Hudaydah port is a turning point in our struggle to recapture Yemen from the militias that hijacked it to serve foreign agendas," a government statement said.

The port is considered a lifeline for the country's war-ravaged population. It serves as an entry point for 70 per cent of foreign humanitarian aid into Yemen, according to the UN. It also provides the rebels with critical access to the Red Sea. About 8,000,000 people in the war-torn country are at risk of starvation.

The Saudi-led coalition accused the rebels of using Hudaydah to smuggle in Iranian weapons. Both Iran and the rebels denied this.

The UN had been trying to get parties to the conflict to reach a deal that would avert an attack on the city. An estimated 600,000 people live in the area.

On June 8, the UN Humanitarian Coordinator for Yemen Lise Grande warned: "In a prolonged worst case, we fear that as many as 250,000 people may lose everything, even their lives."

The Saudi-led coalition intervened in the civil war in Yemen in March 2015 as forces loyal to President Hadi battled the Houthi movement, which champions Yemen's Zaidi Shia Muslim minority.

Since then, 6,385 civilians have been killed and 10,000 others injured, the UN said. The vast majority of those casualties had been the result of coalition air strikes.