A UN donor conference for people affected by war in Yemen – which has been labelled as the “world’s worst humanitarian crisis” – has received pledges of more than $2bn (£1.4bn), close to half of which is promised by Saudi Arabia and the United Arab Emirates, two key protagonists in the conflict.

Despite falling well short of the almost $3bn being called for by the meeting in Geneva, the UN secretary general, António Guterres, hailed the donor conference a “remarkable success”.

The conference came just a day after an airstrike by the Saudi-led coalition on the port city of Hodeidah killed a number of children, in what the UN children’s fund, Unicef, called “one of the deadliest attacks” on minors in the country for years.

“The United Nations has verified the killing of several children in an attack … in the coastal city of Hodeidah in western Yemen,” Unicef said in a statement on 2 April.

“Many children are reported missing as the injured and killed are still being pulled out from the rubble,” it added, amid reports that seven children had been killed.

Guterres told reporters that in addition to the $2bn already committed, multiple countries had promised more donations in the coming months, leaving him “optimistic that we will be able to reach the level that corresponds to the needs”.

Asked if he saw a contradiction in the Saudi stance towards Yemen, Guterres said a country’s humanitarian commitments and military actions should be kept separate.

“We all know that there is a war. We all know who the parties [are] to the war but the two things need to be seen separately,” the UN chief told reporters.

“Independent of the fact that there is a war, there are humanitarian obligations that are assumed by countries,” he said.

“The countries that are also party to the conflict were party to these international efforts to support the people of Yemen.”

Last year’s Yemen appeal for $2.5bn was 73% funded, but the needs have intensified in a country battered since 2015 by a Saudi-led military offensive aimed at repelling Iran-backed Houthi rebels who control the capital.

The UN has said that three-quarters of Yemen’s population – about 22 million people – need some form of aid.

Saudi Arabia and its allies have repeatedly been accused of hitting civilians targets, including hospitals and markets, in their three-year campaign against the Houthis.

Guterres underscored that the only way to ensure that Yemen donor conferences do not continue year after year is for the sides to negotiate a peace deal.

“There was never a humanitarian solution for any humanitarian crisis,” he said. “The solution has always been political.”

The UN’s Yemen envoy, Martin Griffiths, has recently visited Riyadh and Sana’a in hopes of revitalising sputtering peace talks.

“I believe there is an opportunity and that opportunity must be seized,” Guterres said, explaining that Griffiths was “encouraged” by his trip and sees a window for further talks.

According to the UN, 8.4 million people are on the verge of famine in Yemen, where food imports are essential to sustain the population.

The Saudi-led coalition shut down the country’s land, sea and air borders last year in response to a missile attack by the Houthis that was intercepted near Riyadh.

While the coalition has eased the blockade, restrictions on deliveries persist.

“Humanitarians must be able to reach the people who need help the most, without conditions,” Guterres said.

“All ports must remain open to humanitarian and commercial cargo, the medicines, food and the fuel needed to deliver them,” he added, emphasising the need for unrestricted access to the country as well as within it.