Some 3.2 million Iranians have been internally displaced since the U.S.-Israel launched an attack on the country nearly two weeks ago, according to the U.N. High Commissioner for Refugees on Thursday.

"Between 600,000 and 1 million Iranian households are now temporarily displaced inside Iran as a result of the ongoing conflict, according to preliminary assessments," said Ayaki Ito, who heads UNHCR's emergency support team and is the refugee response coordinator for the Middle East emergency.

That represents "up to 3.2 million people," he said in a statement, warning that "this figure is likely to continue rising as hostilities persist, marking a worrying escalation in humanitarian needs."

The United States and Israel launched the first wave of attacks on Feb. 28 in a war that has seen Iran strike targets in multiple countries around the Gulf.

Ito said that most of those displaced were reportedly "fleeing from Tehran and other major urban areas towards the north of the country and rural areas to seek safety."