ERBIL, Kurdistan Region of Iraq - At least 76,000 people have fled their homes in Yemen since July, the UN said Saturday, amid a new flare up between the Iran-backed Houthi rebels and the Saudi-backed government.

“At least 76,000 people have fled their homes since July, up from 46,000 just days earlier,” the International Organization for Migration (IOM) said, adding: “Numbers have nearly doubled overnight. That's four times last week's total, as fighting intensifies. Entire families are on the move, often at night. They have nowhere safe to go.”

The development follows an unprecedented Houthi offensive in recent days in which the rebels have seized the vast majority of Yemen’s Red Sea coastline in a major rout of Saudi-backed forces.

According to the IOM, the west coast and South Taiz are the hardest hit areas, with nearly 50,000 people fleeing from Taiz alone.

Having enjoyed a tentative peace for years following a UN-backed truce in Yemen's decade-long civil war, tensions between Riyadh and the Iran-backed Houthis flared following an airstrike on Sanaa International Airport that prevented an Iranian plane from landing in mid-July.

“Many of these families have been displaced before, some multiple times, over 12 years of conflict. They are exhausted. Their resources are gone. Most fled with nothing but the clothes on their backs. They have left behind homes, livelihoods, and any sense of stability they had left,” the IOM said.

On Saturday, the Houthis seized Yemen’s entire Red Sea coastline after they had expelled Saudi-backed forces from several western districts in a major offensive, including areas around the strategically important Bab al-Mandab Strait.

Riyadh has relied on the Red Sea and the Bab al-Mandab Strait to circumvent Iranian restrictions on the Strait of Hormuz.

About 12 percent of global goods are typically shipped through the Bab al-Mandab Strait at the southern end of the Red Sea. Once shut, everything going to Europe must be rerouted all the way around Africa, driving up time and costs.