Republican presidential hopeful Mitt Romney has vowed to take the White House from President Barack Obama and end four years of "disappointments".
Speaking while racking up a series of primary night victories, he said a "new campaign" was beginning.
"Hold on a little longer. A better America begins tonight," he said.
The presumptive Republican nominee easily won primaries in Connecticut, Delaware, New York, Pennsylvania and Rhode Island.
As the results began to come in on a night with the most electoral delegates at stake since Super Tuesday, Mr Romney took the stage in New Hampshire, the site of his first primary win of the year.
He focused on the forthcoming general election campaign, saying America needed a new direction and a renewal of its greatness.
"Tonight is the start of a new campaign to unite every American who knows in their heart that we can do better," he said.
"The last few years have been the best that Barack Obama can do, but it's not the best America can do.
"Tonight is the beginning of the end of the disappointments of the Obama years and the start of a new and better chapter that we will write together."
His key rivals have all stepped aside from the race, with just Newt Gingrich and Ron Paul remaining in the contest.
Mr Gingrich, a former speaker of the House of Representatives, spoke in North Carolina but gave few clues as to his future in the contest.
He had pinned his hopes on a strong showing in Delaware, but instead polled roughly half of Mr Romney's total.