Mitt Romney launched his campaign as the presumptive Republican presidential nominee after sweeping five primaries on Tuesday (April 24), turning his attention to the November general election showdown against President Barack Obama.

Obama and Romney have already engaged in heavy campaign combat in recent weeks, and that will likely intensify in the six months before the November 6 presidential election. Romney effectively won the Republican race on April 10 when his top rival, Rick Santorum, suspended his White House campaign, but the speech in the general election battleground state of New Hampshire was the first time he claimed victory.

"After 43 primaries and caucuses, many long days and not a few long nights, I can say with confidence, and gratitude, that you have given me a great honor and solemn responsibility," Romney said.

The claim of victory came as Romney swept wins in five Northeastern states-- Connecticut, Delaware, New York, Pennsylvania and Rhode Island-- which have a combined 231 delegates.

The wins move Romney, who entered the night with 695 delegates, closer to the 1,144 he needs to formally clinch the nomination, a milestone that is still weeks away.