(FILES) This file photo taken on June 23, 2016 shows US President Barack Obama speaking in the Brady Press Briefing Room at the White House in Washington, DC. President Barack Obama on June 28, 2016 warned against international "hysteria" following last week's vote for Britain to leave the European Union.In an interview with National Public Radio, the US president said that he respected the results of the referendum. However for Obama, the vote means that "a pause button has been pressed on the project of full European integration." / AFP PHOTO / SAUL LOEBSAUL LOEB/AFP/Getty Images