"It's overwhelming for me to see the huge amount of disenfranchised people who feel the government has failed them," said one government worker who watched results roll in at the U.S. Embassy.
Since British voters decided to leave the European Union in a referendum, more than 4 million people signed a petition calling for a do-over. The government says the "decision must be respected."
"I think that the best way to think about this is a pause button has been pressed on the project of full European integration," President Obama told NPR's Steve Inskeep.