WASHINGTON -- Republican presidential hopeful Newt Gingrich's campaign manager, senior strategists and key aides in early delegate-selection states all resigned on Thursday, a mass exodus that leaves his hopes of winning the Republican nomination in tatters.

Rick Tyler, Gingrich's spokesman, said he, campaign manager Rob Johnson and senior strategists had resigned, along with aides in the early primary and caucus states of Iowa, New Hampshire and South Carolina.

Other officials said Gingrich was informed that his entire high command was quitting in a meeting earlier in the day. They cited differences over the direction of the campaign.

"We had a different vision for victory," Tyler told The Associated Press. "And since we couldn't resolve that difference, I didn't feel I could be useful in serving him."

He said Gingrich was not allowing enough time to campaign in key states.

Scott Rials, a longtime aide who joined the departure, said, "I think the world of him, but at the end of the day we just could not see a clear path to win, and there was a question of commitment."

The upheaval in the campaign is likely to lead to a shakeup in the race for the party's presidential nomination, as well, as rivals reach out for disaffected staff, and possibly for donors who have been aligned with the former Georgia congressman.

Gingrich has long been viewed, by even his closest allies, as a fountain of policy ideas but a man who is unable to avoid speaking in ways that spark unwelcome controversy.

The presidential candidate himself wrote in a post on Facebook, "I am committed to running the substantive, solutions-oriented campaign I set out to run earlier this spring. The campaign begins anew Sunday in Los Angeles."

The Des Moines Register reports:

Newt Gingrich's entire team of paid Iowa campaign staff, as well as his national spokesman and senior aides in New Hampshire and South Carolina, have resigned en masse, a staffer told The Des Moines Register.

Meanwhile, Georgia Democrats are out with a statement looking to capitalize on the shake-up:

Campaign staffers of Newt Gingrich's flailing presidential bid walked off the job en masse today, demonstrating the power of organized labor and teamwork while serving in a hostile work environment. ... "After three grueling weeks on the campaign trail, Gingrich needed a vacation and his entire staff needed to quit the campaign entirely," concluded Gray. "I don't know which is worse- his work ethic or his people skills."

Even before the sudden departures, Gingrich's campaign was off to a notably rocky start. Within days of formally announcing he would run, he was assailed by conservatives for criticizing a plan to remake Medicare that Republicans pushed through the House.

He called the author of the plan, Rep. Paul Ryan, to apologize but did not back off his objections.

Within days, he had dropped from sight, embarking on a cruise to the Greek Isles with his wife, Callista, while rivals for the Republican nomination kept up their campaign appearances.

He returned to the United States earlier in the week to confront a rebellion that had been brewing for some time among the senior echelon of his campaign.