The first US Cabinet member to visit Somalia since 2015 called on the international community on Sunday to give more as the eastern African nation faces famine.
"The US cannot do this alone," said the US Ambassador to the UN, Linda Thomas-Greenfield.
Ms Thomas-Greenfield urged "other donors and the world to go bigger and be bolder," adding "this is the moment to bolster your humanitarian contributions".
The UN envoy, who finished her African tour on Sunday, said that the US would provide more than $40 million in funding to Somalia as it battles a famine.
Ms Thomas-Greenfield visited Mozambique, Ghana, Kenya and Somalia as part of President Joe Biden’s commitment to expand and modernise US partnerships in Africa.
She met humanitarian partners and leaders from UN agencies, the wider international NGO community and local leaders to discuss food insecurity, refugees and other humanitarian needs across the continent.
Last year, the US provided more than $2.5 billion of lifesaving assistance to the Horn of Africa, and $1.3 billion of that directly to Somalia.
Ms Thomas-Greenfield said in the capital Mogadishu that the humanitarian situation in Somalia was “as dire as any in the world right now".
“Famine is the ultimate failure of the international community," she said.
The ambassador said she would not name the countries to which she was referring, but she had asked the UN to approach those countries, and others, so that they might identify who could give more.
“I’m not going to name and shame today, but the countries know who they are,” Ms Thomas-Greenfield said.
The UN said almost half of Somalia’s 17 million population faced acute food insecurity, with 300,000 expected to experience famine this spring.
More than 900,000 have been living in areas under control of Al-Qaeda affiliated Al Shabab, complicating aid access.
Al Shabab militants have been trying to overthrow Somalia's central government for almost 15 years.