UNITED NATIONS, June 24 (Xinhua) -- Israeli firebombs displaced families in Gaza overnight, and the expansion of the so-called Yellow Line prevented families from returning to their homes, UN humanitarians said on Wednesday.

People were displaced overnight in the Beit Lahia area of North Gaza governorate, the UN Office for the Coordination of Humanitarian Affairs (OCHA) stated.

Around midnight, about 30 households reportedly fled when tanks advanced toward Al Atatra Junction in Beit Lahia. Reportedly, a quadcopter drone dropped incendiary munition that set three tents ablaze, said OCHA.

While most families could return after the troops withdrew, six households remained displaced because a yellow cement block was installed near their places of residence. Setting up such blocks signals the expansion into populated areas of the so-called Yellow Line, where lethal force has often been used, said the office.

"Humanitarian partners are supporting families that are newly displaced or have otherwise lost their belongings," said OCHA. "Last week, partners responded to alerts that affected 135 households. After quickly assessing their individual needs, they provided people with tents, blankets, hygiene and dignity kits, jerrycans and tarpaulins through a Rapid Joint Distribution Mechanism."

Most of the newly affected families were impacted by strikes. Dozens of other families were displaced from areas along the "Yellow Line" following the advancement of Israeli forces and placement of yellow cement blocks. A smaller number of people received help following domestic fires or flooding, said OCHA.

The office said the vast majority of Gaza's 2.1 million people remain displaced and warned that longer-lasting shelter requires approvals to bring into the strip construction materials and equipment to remove rubble and clear explosive ordnance. ■