Sanaa, Feb 12 : Escalation of fighting between Yemen's government forces and the Houthi militia in the oil-rich province of Marib has displaced nearly 400 families in just three days, an official said. "During the past three days around 400 families left their villages and residential houses due to the non-stop intense battles in the province," the official of Marib's local authority told Xinhua news agency on Thursday. The displaced families left the district of Sirwah amid the exchange of indiscriminate artillery shelling. "Many families are now threatened by a second displacement wave and they are seeking to flee again to find other safe areas away from fighting," the official added. On Wednesday, two shells landed on a displacement camp housing about 225 families in Marib, causing no casualties. Yemeni officials in charge of the internally displacement camps in the government-controlled province of Marib urged the international humanitarian organisations to pressure the Houthis to stop targeting the displaced people. The Iran-allied Houthi rebels stepped up their military operations and launched an large offensive to seize the province of Marib controlled by the Saudi-backed Yemeni government. The Houthis' military escalation followed Washington's indication of removing the group from the terrorist list, which will reverse the decision by the administration of former US President Donald Trump. Yemen has been mired in civil war since late 2014 when the Iran-backed Houthi rebels seized control of several northern provinces and forced the Saudi-backed government of President Abd-Rabbu Mansour Hadi out of the capital Sanaa. The Saudi-led coalition intervened in the Yemen conflict in March 2015 to support Hadi's government. The war in Yemen has killed tens of thousands of people, displaced 4 million others, and pushed the country to the brink of famine. /IANS