BOSTON — His reach for the presidency thwarted, Mitt Romney stayed out of sight late Tuesday as news organizations including The Associated Press announced that President Barack Obama had won a second term.

Dejected Romney supporters milled around a hotel ballroom where the Republican hopeful had planned to declare victory and groaned as key battlegrounds moved Obama’s way.

Obama’s victory in closely fought Ohio narrowed Romney’s path to the 270 electoral vote. The Democrat also was declared the winner in other swing states including New Hampshire, Wisconsin, Colorado and Iowa. Michigan and Pennsylvania, which Republicans hoped to put in play, stayed in Obama’s camp as well. Florida and Virginia remained too close to call.

Romney supporters cheered a win in North Carolina, which Obama captured four years ago. But it was a rare prize in an evening that broadly favored the presidency.

Romney staffers almost all expressed shock or surprise that so many states had voted for Obama. Republican vice presidential nominee Paul Ryan was watching returns with family in the same hotel where Romney and his family watched results.

The Republican nominee had already written a 1,118-word victory speech that he thought would conclude his yearslong quest for the presidency. Earlier Tuesday, Romney said he had no regrets no matter the outcome.

“I feel like we put it all on the field. We left nothing in the locker room. We fought to the very end, and I think that’s why we’ll be successful,” Romney told reporters aboard his plane as he flew from Pittsburgh to Boston, where preparations were underway for a big election night event at the Westin Boston Waterfront Hotel.

Romney’s son Craig appeared briefly in the ballroom early in the evening to warm up the crowd. Craig Romney said that after his father dropped out of the race for the GOP nomination in 2008, Ann Romney had been opposed to another run but eventually changed her mind.

“We’re grateful that she convinced him to get into the race because we know that my dad has been uniquely prepared,” he said.

The GOP nominee had spent Election Day doing a last-minute round of campaigning in one state he’s showered with attention, Ohio, and another he’s largely ignored, Pennsylvania. After voting near his Boston-area home, Romney was betting that an eleventh-hour appeal to working-class voters in both states would help him defeat Obama.

“This is a big day for big change,” Romney told staffers and volunteers at a Cleveland-area campaign office.

On his campaign plane in between flights, he worked on his speech. He said he hadn’t written a concession speech, though he acknowledged the results might not come out in his favor. “Nothing is certain in politics,” he said.

Ryan followed a similar strategy for courting voters on Election Day. After voting in his Wisconsin hometown, the GOP vice presidential hopeful joined Romney in Ohio before a scheduled solo visit to Richmond, Va.

Asked about the hectic schedule in recent days, Ryan said of Romney: “He’s kind of operating on fumes.”

Romney’s focus on Ohio is not a surprise. He has spent more time campaigning there over the last year than any other state. And no Republican has won the presidency without carrying the Midwestern battleground.

But Romney has spent very little time in Pennsylvania, which hasn’t supported a Republican presidential contender in nearly a quarter-century. As polls showed the race tightening there, Romney launched a statewide advertising campaign just last week.

Dismissed as desperation by Democrats, the Pennsylvania trip will at the very least send the message that Romney did all he could to deny Obama a second term.

“We can’t let up now. We need to keep going until the final polls close tomorrow night,” Romney political director Rich Beeson wrote supporters Monday. “With an election this important, let’s leave it all on the field.”