NEW YORK, March 30 (Reuters) - Donald Trump has been indicted by a Manhattan grand jury after a probe into hush money paid to porn star Stormy Daniels, becoming the first former U.S. president to face criminal charges even as he makes another run for the White House.

The charges from an investigation led by Manhattan District Attorney Alvin Bragg come as Trump seeks the Republican nomination to run again in 2024.

The specific charges are not yet known, as the indictment remains under seal. CNN reported Trump faces more than 30 counts related to business fraud.

Trump said he was "completely innocent" and indicated he would not drop out of the race. He accused Bragg, a Democrat, of trying to hurt his chances of winning re-election.

"This is Political Persecution and Election Interference at the highest level in history," he said in a statement.

Shortly after, Trump appealed to supporters to provide money for a legal defense. He has raised over $2 million, according to his campaign, since he incorrectly predicted on March 18 that he would be arrested four days later.

The charges will likely be unsealed by a judge in the coming days. Trump will have to travel to Manhattan for fingerprinting and other processing at that point.

Bragg's office said it had contacted Trump's attorney to coordinate a surrender, which a court official said would likely occur next Tuesday.

Trump's lawyers Susan Necheles and Joseph Tacopina said they will "vigorously fight" the charges.

The Manhattan investigation is one of several legal challenges facing Trump.

The charges could hurt his presidential comeback attempt, as the mug shot from his arraignment and any visuals from his courtroom appearances could provide fodder for rivals.

Trump could use the case to stoke anger among his core supporters, though other Republican voters might tire of the drama.

Some 44% of Republicans said he should drop out of the race if he is indicted, according to a Reuters/Ipsos poll released last week.

Trump's allies and fellow Republicans blasted the indictment as politically motivated, while Democrats said he is not immune from the rule of law.

The White House declined to comment.

Outside the courthouse, several protesters silently held signs criticizing Trump. Authorities bolstered security around the courthouse after Trump called for nationwide protests on March 18, recalling his charged rhetoric ahead of the Jan. 6, 2021, attack on the U.S. Capitol.