BOSTON – Republican Mitt Romney conceded defeat in the presidential contest early Wednesday, saying the nation had chosen Barack Obama to remain president for another term and that it was time for the nation to unite behind him.

"This is a time of great challenges for America, and I pray that the president will be successful in guiding our nation," Romney said.

Romney spoke to cheering supporters in a hotel ballroom in Boston. The former Massachusetts governor said he was proud of the campaign he had run but that voters had made another choice.