Nearly 2 million displaced Yemenis are under threat as Iran-backed Houthi rebels intensify their offensive near the northern city of Marib.

The rebels are pushing towards the city on multiple fronts, seeking to take the last government-controlled major city in the north, a pro-government military source said.

The rebels have reportedly shelled the camps for the displaced, killing people and causing panic.

Local and international humanitarian organisations are warning of imminent disaster if the rebels continue their attacks.

“The city hosts 141 IDP camps [with] over 2 million residing in these camps that include the largest IDP camp in Yemen – Al Jufainah settlement located south-east of Marib that hosts 8,000 families,” Najeeb Al Saadi, the head of the executive unit in Yemen for internally displaced people, told The National. “The situation will worsen and get more complicated if the Houthis continue their offensive towards the city.”

He described Marib as “the last safe haven” for the millions of Yemenis who fled from across the country’s north as the rebels took ground after their coup d'etat in 2014 and ensuing fighting.

The International Organisation for Migration reported that between January and May 9,500 more households were displaced to Marib from nearby areas – many for the second time – as fighting increased .

“These people have nowhere to flee to if the Houthi rebels take control over [Marib city],” Mr Al Saadi said.

International aid groups are also sounding the alarm.

The International Committee of the Red Cross (ICRC) said it is witnessing an intensification of the fighting around the city which hosts millions of IDPs.

“We call upon the warring parties to spare the overcrowded city such escalation to provide protection to civilian lives. They [combatants] must respect the rules of war and international humanitarian law,” Yara Khawaja, ICRC's Yemen spokesperson, said.

She said an “escalation will cause a new massive round of displacement”.

“The IDPs residing in the camps in Marib are already suffering from water, food and medicine shortages in addition to troubles caused by the severe flooding that hit the city in July and in August, resulting in the loss of lives and huge devastation in the camps in the city,” Ms Khawaja said.

The ICRC's call came as Yemeni human rights activists launched a social media campaign using the hashtag #Yemeni_IDPs_lives_Matter.

The activists called on the UN and special envoy to Yemen Martin Griffiths as well as the international community to put pressure on the Houthi rebels to halt the offensive on Marib to avert a fresh disaster.

“The IDPs camps in Marib city have been a target for the Houthis as the clashes intensified around the city. They repeatedly shelled the IDPs camps in the city with heavy weapons and ballistic missiles which resulted in losses of dozens of lives. Such crimes violate the international humanitarian law and Geneva Conventions. They must be stopped and held accountable,” Huda Al Sarari, a Yemeni lawyer and human rights activist who took part in the social media campaign, told The National.

The military source described the push that has seen rebels step up their offensive in the south of the city.

“The Houthi rebels have been pushing towards Marib city from three directions,” the source said. “They have been leading major attacks from Al Hazim city in Jawf to the north of Marib and they have pushed an offensive from the southern areas between Marib and the province of Bayda while trying to reach the city from Sirwah area east of the city.”

Ms Al Sarari questioned why more has not been done to halt the rebel offensive.

“They [Houthi rebels] have been escalating and pushing towards Marib since January 2020 meanwhile the UN, its envoy to Yemen and the international community watch them silently. Why?” she asked.