WASHINGTON – The entire top echelon of Newt Gingrich’s presidential campaign resigned Thursday, a stunning mass exodus that left his bid for the Republican nomination in tatters. But the former House speaker vowed defiantly to remain a candidate.

“I am committed to running the substantive, solutions-oriented campaign I set out to run earlier this spring,” Gingrich said in a posting to his Facebook page. “The campaign begins anew Sunday in Los Angeles.”

Rick Tyler, Gingrich’s spokesman, said that he, campaign manager Rob Johnson and senior strategists had all quit, 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 at his headquarters in Washington. They cited differences over the direction of the campaign.

“We had a different vision for victory,” Tyler said. “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, an 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 was likely to lead to a shake-up 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 Gingrich.

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.