Image caption Newt Gingrich said he was still in the race

A number of senior aides have left the 2012 presidential campaign team of Republican former House Speaker Newt Gingrich, citing strategic differences.

"When the campaign and the candidate disagree on the path, they've got to part ways," said ex-aide Rick Tyler, according to the Washington Post.

The news will hit Mr Gingrich's hopes of being the Republican nominee to challenge President Barack Obama.

But he said his "solutions-orientated" campaign was still moving forward.

Question of commitment

His campaign got off to a halting start when he criticised a plan popular among Republicans to slash and privatise a healthcare programme for the elderly.

Staff were also reportedly concerned after he took a recent holiday cruise.

He's a survivor but it is hard to see how he survives this Can Newt overcome desertion?

Mr Gingrich's campaign manager Rob Johnson and his entire senior staff, including strategists in early primary election states, were among those to quit on Thursday.

Scott Rials, a longtime aide who joined the departure, told the Associated Press that he doubted Mr Gingrich's ability to win the nomination.

"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," he said.

On his Facebook page on Thursday, Mr Gingrich indicated he would stay in the race.

"I am committed to running the substantive, solutions-oriented campaign I set out to run earlier this spring," he wrote. "The campaign begins anew Sunday in Los Angeles."

With the Republican primary campaign beginning to take shape, the lack of a core team could seriously hinder Mr Gingrich's chances at winning the Republican nomination, analysts say.

Mr Gingrich remained widely respected in the party for leading congressional Republicans out of 40 years in opposition in 1994, although he lost the speaker's gavel in 1998 after the party took significant losses.

After launching his White House bid in May, he quickly drew heavy criticism from virtually the entire national Republican establishment for criticising a Republican congressman's proposal to overhaul the popular Medicare healthcare programme.