Tens of thousands of people have been forced to flee their homes since fighting intensified in Yemen last week, the United Nations said on Friday, with the number doubling in a matter of days. Iran-backed Houthi rebels, who for years have controlled much of northern Yemen, launched a full-scale offensive last week against Saudi-backed government forces, scoring one victory after another in fighting that has left hundreds dead. Since the fighting intensified, “at least 46,000 people have been displaced.” On Tuesday, the UN agency had estimated the figure at around 18,500. The announcement came after the Houthis took control of the strategic Red Sea port city of Mokha on Thursday, according to sources who spoke to AFP, Associated Press and Reuters news agencies, before seizing a key island in the middle of the Bab el-Mandeb Strait on Friday. Saudi Arabia responded with dozens of airstrikes, the last two hitting Mokha airport, Houthi media reported Friday. Displacements occurred along the western coast and Taiz areas, the IOM said, also noting reports of large numbers of people seen leaving Mokha with their belongings overnight on Friday. The agency said people also appeared to be moving north. cut.IOM chief Amy Pope warned that “as the fighting spreads, it is increasingly difficult to reach people with life-saving assistance.” “We urgently need safe and unimpeded access,” he said in the statement. “All parties must protect civilians and humanitarian workers, and safeguard the supplies, vehicles and facilities we depend on to deliver aid.”