U.S. Sen. Rand Paul promised to be a different kind of Republican on Tuesday, launching a 2016 White House bid by saying he would stand up for individual freedoms that are being trampled by "the Washington machine."

The first-term senator from Kentucky, a libertarian with a reputation for challenging party orthodoxy, criticized Republicans in Congress and the White House for helping to drive up the federal debt and reducing personal liberties.

"The Washington machine that gobbles up our freedoms and invades every nook and cranny of our lives must be stopped," he told cheering supporters on a flag-draped stage in Louisville, Kentucky.