Rock star Bono warned legislators on Capitol Hill Tuesday that the Syrian refugee crisis could lead to the end of European unity as the world knows it if the United States does not take action.

"Europe hasn't mobilized at the level it needs to, but I think that's about to change," Bono told a Senate Appropriations subcommittee. "I'm talking about an existential treat to Europe the likes of which we haven't seen since the beginning of the 40s."

He went on the explain that the United States should take a more active role in the current refugee crisis, as it threatens to destabilize Europe, and that a "permanent temporary solution" won't be nearly enough. He advocated increased humanitarian support, welcoming of refugees into developed nations and increased development assistance for countries affected by conflict.

"The very idea of European unity is at risk here," Bono warned. "If the Middle East catches fire, the flames jump any border controls."

The U2 frontman spoke about his experience touring the Middle East and Africa with Sen. Lindsey Graham, R-S.C., and also drew on his experience from co-chairing the ONE campaign, a international advocacy organization that works to combat extreme poverty and preventable disease.

"Aid in 2016 is not charity. It is national security," Bono told the committee in his opening remarks. "Though of course we know that aid alone is not the answer, it is also true that when aid is structured properly, with a focus on fighting poverty and improving governance, it could just be the best bulwark we have against the extremism of our age."

Bono's remarks followed Graham's, who opened by saying, "this is what it feels like to be chopped liver," noting the unusually packed room and large media presence for Bono's testimony.

Other members of the committee were star struck by the Irish musician as well, as Deputy Secretary of State Antony Blinken joked he had once "only dreamed" of opening for Bono, so he was honored to have the opportunity in Washington. United Nations Deputy Commissioner for Refugees Kelly Clements noted that Bono's music defined her high school years prior to giving her testimony.