Top diplomats from Switzerland and Sweden joined with UN chief Antonio Guterres to host Tuesday's conference in Geneva, where the United Nations hopes to reach a goal of $2.1 billion (1.93 billion euros) for a relief appeal it launched this year. By the end of the event, Guterres said that about $1.1 billion had been raised, meaning more efforts would be necessary to achieve the stated goal.

The the opening of the meeting, Guterres said fast action was necessary if more people in Yemen were not to die from war-related causes.

"We are witnessing the starving and the crippling of an entire generation. We must act now to save lives," he said.

The UN's humanitarian arm, OCHA, says that 18.8 million people in Yemen are now "in need of humanitarian or protection assistance" after a simmering conflict erupted in 2014.

More than 10,000 civilians have been killed and some 3 million displaced in a war pitting Shiite, Iran-backed Houthi rebels and forces allied with ex-President Ali Abdullah Saleh against fighters loyal to exiled President Abed-Rabbo Mansour Hadi.

Multi-party conflict

The humanitarian crisis in Yemen has been exacerbated since a Saudi-led coalition of mostly Arab Sunni countries joined the fray on Hadi's side in March 2015, carrying out air strikes on the Houthis and allied forces that have claimed many civilian casualties and devastated the country's infrastructure.

The coalition is supported by the USA, Great Britain and France, among others. Germany is also involved in the conflict, selling weapons to the Saudis and other warring parties.

The power vacuum left by the conflict has also allowed various extremist organizations, including al Qaeda and the so-called "Islamic State" (IS), to enhance their presence in the country.

Read more: Yemen's shameful war

Children at risk

The war has brought the already impoverished country to the brink of famine, with UN human rights expert Idriss Jazairy telling DW that 85 percent of the country's 27.4 million inhabitants were suffering under food and medicine insecurity.

Of these, "7 million do not know where their next meal will come from," while 2 million "are directly threatened by starvation," Jazairy said, adding that this group included almost 500,000 children.

In a joint statement on Tuesday, the UN children's agency UNICEF and the World Food Program (WFP) said nearly 2.2 million children in all were malnourished.

On average, one child under the age of five dies in Yemen every 10 minutes of preventable causes, the UN says.

Read more: Yemen's conflict all but ignored by the West

Access problems

Experts say that even if the money pledged at Tuesday's conference reaches the set goal and the donor countries make good on their vows, bringing assistance to Yemen will remain difficult.

Marten Mylius, the emergency coordinator for the Middle East for the aid organization CARE, told DW that the problems with access were largely caused by the Saudi-led coalition, which has imposed a blockade on Yemeni ports and airports. The fact that the most important port for imports, Hodeida, was in the hands of the Houthi rebels and their allies, did not help, Mylius said, because the region was often bombed by coalition warplanes, which had already destroyed cranes and other infrastructure.

In addition, many observers fear that the coalition could soon try to wrest the port from the Houthis, which would shut down an important lifeline for the Yemeni people.  

The Yemeni conflict was triggered when the Houthis seized the capital, Sanaa, and some other areas in 2014, forcing the internationally recognized government under Hadi to leave the country.