Dozens of people have protested outside the US Embassy in Dublin against cuts to USAID which they say will cost thousands of lives.
President Donald Trump announced the freezing and suspension of payments by the US Agency for International Development claiming that billions of taxpayers' dollars are being stolen through the organisation.
But activitists around the world have been outraged by the decision to cut funding for essential medicines for millions of people living with HIV, particularly in Africa.
At the protest, HIV activist Robbie Lawlor said: "It's an absolute catastrophe. But it's not only HIV, it's TB, it's malaria, nutritional programmes, it's educational programmes.
"This is impacting the lives of so many people, and yet we're not hearing a whimper out of the Irish Government. We're not hearing a whimper out of the European Union.
"So we are here today to say that Ireland needs to step up and it needs to be a leader, and we should convene our EU partners to say that EU should, must come together to overcome this catastrophe that we're seeing."
Dr Nadine Ferris France, of the Irish Global Health Network, said: "I'm just back from Kenya last week, where we heard in Kenya that, overnight, 44,000 healthcare workers are affected by this, by this gap, and the clinics, the community health clinics, have closed all over the country.
"Speaking to colleagues and friends in Zimbabwe, we know we work with young people living with HIV who take their medication every day and this week they're not sure if they're going to have medication. So I think the impact is absolutely huge."
She called on the Irish Goverment to take practical steps.
"We need collaboration ... we have a really strong history of leading as Ireland and we have quite a credibility in terms of diplomacy. So I think bringing those skills to bear and trust, bringing the EU together would be really important. Solidarity is needed more now than ever, ever before."
Irish Government needs 'to act' - activist
Mr Lawlor said the situation could not be more urgent
"I heard, talking to a woman from Uganda this morning, who went with her child to collect her child's HIV treatment, and she was torn away because there was no syrup for the child.
"The thing about HIV treatment is you need to take it every day to ensure that you can live because you know you can get resistance to HIV treatment, well then you can't go on to the next treatment if they don't even exist in your country, she is just so fearful of her child's life.
"So when we hear about these numbers, what we're hearing is just millions of people without treatment, but these are millions of people who will die.
"It is catastrophic, and it's not happening next week. It's not happening next year. It's happening now, and the Irish Government need to act now. That is what this protest is about."
