The European Union's top diplomat says it's "completely unrealistic" to think that President Bashar Al-Assad could retain power over any future government in a post-war Syria. EU foreign policy chief Federica Mogherini said Monday that "it seems completely unrealistic to believe that the future of Syria will be exactly the same as it used to be in the past." But, she added, "it is for the Syrians to decide, that's clear." Her remarks in Luxembourg come as Washington appears to be softening its line against Assad. In London Friday, US Defense Secretary Jim Mattis suggested that Assad's status is not the most important question right now. International donors gather in Brussels on Wednesday to drum up financial aid and support for a lasting solution to the six-year-long conflict. Earlier US Ambassador to the UN Nikki Haley said that America wants to bring Assad to justice as he used chemical weapons and killed his own people. Haley, the first Indian American to hold a Cabinet level position in any presidential administration, said human rights was a very important issue for the Trump Administration. "Our goal is we want to bring Assad to justice. We want them to pay for the crimes that he's done. We're going to continue to let Russia know how dangerous it is to keep Assad in power," Haley told ABC News in an interview. "Assad is not going away, but we're not going to stop beating up on him. We're not going to stop saying that the way he treats the people in Syria is wrong, that he has actually killed his own people and America will never stand for that," Haley said. She said Assad was always a priority for the US. "He has done terrible things to his own people. He has used chemical weapons on his own people. He continues to be a hindrance to peace in Syria. And that is something the administration strongly believes," she said. Haley said the US needed to start putting pressure on Russia and Iran to get Tehran out of the equation. "We need to get the Iranian influence out of there," she said. "If you look at the Syrian conflict, how did it start? It was a group of teenagers that were the ages of 10 to 15 that went and spray painted graffiti about their government on a wall. With that, the police came in, picked up those boys, beat them up, pulled their nails out, kept them overnight and returned them bloodied to their parents," she said. "Their parents went out to the streets and protested. Other parents saw that and responded. That is what is led to the overall conflict in Syria was all because the government wasn't treating their people well. "And so what I'm trying to bring attention to is that human rights is a big important part of how to prevent conflict in the first place if we focus on how the governments are treating their people," Haley said. — Agencies