At least 46,000 people have been displaced in southwestern Yemen since fighting intensified last week between Houthi forces and Yemen’s government troops, the International Organization for Migration said Friday, as the conflict pushed thousands of civilians from coastal and inland communities.

The figure, based on displacement data collected through Thursday, covers areas along Yemen’s western coast and in Taiz province. It has more than doubled from the roughly 20,000 people the IOM had reported displaced earlier in the week.

The latest escalation began on September 3, when Houthi forces launched attacks across western Taiz and areas near the Red Sea coast. The fighting has since spread towards Mokha and the Bab al-Mandab Strait, a major maritime chokepoint connecting the Red Sea with the Gulf of Aden.

The conflict has also brought major territorial changes. Houthi forces entered the strategic port city of Mokha on Thursday, according to residents cited by The Associated Press and other reports. The development has increased concerns over the security of shipping routes near Bab al-Mandab.

Hundreds of people have reportedly been killed since the fighting began, although casualty figures vary. AFP reported on September 10 that at least 500 people, mostly fighters, had been killed based on figures from sources on both sides.

The humanitarian consequences have been immediate.

IOM Director General Amy Pope said families were being forced to flee for a second or third time after losing most or all of what they had rebuilt during years of conflict.

The agency said large numbers of people were seen leaving Mokha overnight carrying personal belongings. It also reported that the Mokha-Taiz road, a key supply route, appeared to have been cut, further restricting movement and humanitarian access.

New displacement has also been recorded in Lahj and Aden, while some families have moved north towards Ibb. Entire villages in Maqbanah, Al Ma'afer and Jabal Habashi districts were reportedly emptied as fighting approached populated areas.

The escalation has also disrupted humanitarian operations. IOM said it temporarily suspended all field movements and operational activities from Friday because of the deteriorating security situation.

Pope called for safe and unimpeded humanitarian access and urged all parties to protect civilians, aid workers, vehicles, warehouses and other facilities used to deliver assistance.

“Families are arriving with nothing: no shelter, no food, no way to know if it’s safe to go back,” IOM Yemen Chief of Mission Abdusattor Esoev said in an earlier update, when the agency had recorded about 18,500 newly displaced people in Taiz and Al-Hodeidah after the September 3 escalation.

The rapid increase illustrates the speed at which the latest offensive has expanded. IOM had recorded 1,644 newly displaced people across Yemen between August 23 and 29, with Taiz accounting for most of those movements, before the much larger wave triggered by the September escalation.

The fighting is unfolding against a wider regional backdrop in which the Bab al-Mandab has gained further strategic importance as maritime traffic through the Strait of Hormuz has been disrupted by the wider Middle East conflict.

For civilians in western Yemen, however, the immediate concern is more basic: finding somewhere safe to go as fighting cuts roads, empties communities and places further pressure on an already stretched humanitarian response.