Civilian deaths in Yemen have surged dramatically since June after the Saudi-led coalition began an offensive to take the key port city of Hodeidah from Houthi rebels.

According to the figures, collected by the Armed Conflict Location and Event Data project (Acled), civilian deaths in the Yemeni conflict have increased by 164% in the four months since the Hodeidah offensive started, claiming the lives of about 166 people a month.

The group’s analysis suggests Hodeidah has become the most violent frontline in the four-year conflict. In recent months, about one-third of the total conflict-related fatalities have been recorded in the governorate, reflecting the bitterness of the struggle for the key port and its surrounding environs.

Attempts to negotiate a ceasefire led to a temporary pause in the summer offensive, but the failure of peace talks in Geneva convened by Martin Griffiths, the UN special envoy for Yemen, led to a resumption of hostilities on 7 September.

The coalition-led efforts have focused on several key points around the city, including a battle for control of the Kilo 16 road junction linking Hodeidah to Sana’a, a key supply line for the Houthis controlling the port.

The sharp rise in casualties noted by Acled was cited by the International Rescue Committee (IRC) in renewed calls to the UN general assembly, which met in New York this week, to bring an end to Yemen’s war.

“August was the most violent month of 2018 in Yemen with nearly 500 people killed in just nine days,” said Frank McManus, the IRC’s Yemen director, who added that, “since 2015, the coalition has undertaken 18,000 airstrikes – one every 99 minutes – one-third of which have hit non-military targets”.

McManus said: “The protection of civilians and civilian infrastructure is not a luxury; it is an essential provision of international law. When these laws fail, civilians suffer. Calls from members of the UN security council for all conflict actors to respect international law and protect civilians ring hollow in the face of evidence from the ground in Yemen. The world needs a wake up call on Yemen and a new strategy to prevent the suffering of civilians.

“As we speak, fighting inside the critical port city of Hodeidah is increasing and the consequences are dire. A siege will effectively block humanitarian aid from reaching the 22 million people in need and could trigger famine. This week the UN warned that we are losing the fight against famine in Yemen and, with the humanitarian crisis plummeting to new depths, all efforts must be focused on securing a ceasefire.”

The new casualty figures came even as the Saudi-led coaltion insisted it was doing everything to minimise civilian deaths in Hodeidah.

Military spokesman Col Turki Al-Maliki announced on Monday that three humanitarian corridors between the former capital that was seized by the Houthi militia in 2014 and the country’s biggest port on the Red Sea have been set up in cooperation with the UN Office for the Coordination of Humanitarian Affairs (OCHA).

“The coalition is working with OCHA in Yemen to establish safe humanitarian corridors to help in the delivery of aid … between Hodeidah and Sanaa,” Al-Maliki told a press conference in Riyadh.

International NGOs have echoed warnings about the escalating scale of the humanitarian crisis in Yemen after Mark Lowcock, the UN humanitarian chief, last week told the security council that the country is at a “tipping point” for the risk of a “massive loss of life” because of famine.

In a statement to the UN general assembly, 14 groups including Save the Children, Oxfam and Mercy Corps said: “After almost four years of conflict, and despite all efforts to halt displacement, hunger and disease, Yemen remains the worst humanitarian crisis on earth. The suffering inflicted on Yemeni people is entirely manmade and will continue to deteriorate rapidly on all fronts without actions to end the violence.

“Increased fighting risks pushing the country into utter devastation: The ongoing escalation around Hodeidah jeopardises the safety of civilians and threatens the channels for critical fuel, food and medical supplies to the rest of the country. It is crucial that this remains open. The lives of millions of Yemeni women, men and children hang on this lifeline.

“Civilians continue to bear the brunt. Civilians and civilian infrastructure, such as markets, hospitals, school buses and mills continue to be hit by all parties with impunity, as reported by the UN group of eminent experts on Yemen.

“Attacks on schools and hospitals continue, with over 1,800 schools directly impacted by the conflict, including more than 1,500 that have been damaged or destroyed and 21 used by armed groups.”