WASHINGTON - Protesters nationwide are staging massive rallies from New York to Los Angeles to support special counsel Robert Mueller and the Russia investigation, which they fear may be ended due to the firing of Attorney General Jeff Sessions.

The about 900 protests Thursday are part of a coordinated effort by a large number of liberal groups who came together and for months have been planning a "rapid response" to protect Mueller.

The group's website, titled "Nobody is above the law - Mueller protection rapid response," detailed plans for massive protests should something happen that would put Mueller in jeopardy. The group says that something happened when Sessions was fired and replaced with interim Attorney General Matt Whitaker.

"Donald Trump has installed a crony to oversee the special counsel's Trump-Russia investigation, crossing a red line set to protect the investigation," the group says on its website. "Our hundreds of response events are being launched to demonstrate the public demand for action to correct this injustice."

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Organizers say the naming of Whitaker is a "deliberate attempt to obstruct the special counsel's investigation."

President Trump, though, has given no indication that he would end the investigation, which he has dubbed a "witch hunt." But, the ousting of Sessions will give the president authority to replace him with someone who could attempt to derail the investigation, which is also examining possible obstruction of justice by the president.

Meanwhile, concern has grown over his interim replacement and the authority he now holds over the high-profile probe.

Whitaker has faced a barrage of criticism over his past remarks about the scope of the investigation, including that the Justice Department could choke off funding for the office, which would lead to the inquiry’s slow death, and that Mueller would be crossing a "red line" if he examined the Trump family's finances.

On Thursday, attorneys general in 18 states sent a request to Whitaker requesting he recuse himself from the investigation due to his previous comments.

"Because a reasonable person could question you impartiality in the matter, your recusal is necessary to maintain public trust in the integrity of the investigation and to protect the essential and longstanding independence of the department you have chosen to lead," the letter reads.

In New York, a protest in Times Square attracted several hundred people calling for Mueller's protection.

Those gathered chanted slogans including "Hands off Mueller" and "Nobody's above the law" before marching downtown. They held signs saying "Truth Must Triumph" and "Repeal, Replace Trump."

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It was a similar scene in Ohio, where hundreds gathered in downtown Cincinnati, some clutching signs calling for Trump to pay deference to law and order.

Some, though, believe he's already violated the law by inserting Whitaker as attorney general.

Whitaker's appointment as the top law enforcement chief in the country came without approval from the Senate, which Patricia Klingenberg, who organized Cincinnati's rally, said is "probably unconstitutional."

Phil Heimlich, a former assistant prosecutor in the area and Cincinnati councilman, said the leadership change-up should worry everyone.

"It's very obvious to me that it's an attempt to derail the prosecution," he later told The Enquirer. "Just the act of issuing indictments can't go forward without Whitaker. He can stop everything."

In Vermont, a rally brought traffic to a standstill in downtown Burlington as protesters marched from the Federal Building on Elmwood Avenue to City Hall, chanting "Let Bob do his job!" and "Two, four, six, eight! We want Mueller to investigate!"

Prosecutors must be able to examine evidence and make independent decisions, Eugene Bergman, a recently retired Burlington assistant city attorney, told the crowd.

"The integrity of our system, the rule of law itself, depends on this freedom from political pressure," he said. "When the political boss exerts or tries to exert control of a prosecutor, it is an act of corruption."

Former Gov. Madeline Kunin told the gathered crowd that giving Whitaker oversight of the investigation was manipulative and wrong.

She told the marchers to prepare for a long fight.

"We have to be vigilant," Kunin said. "We have to persist, and persist we will."

Those in Tennessee also gathered for the cause. In Nashville, protesters held up signs and chanted for a "Nobody is Above the Law Rally."

"Donald Trump just crossed a red line, violating the independence of the investigation pursuing criminal charges in the Trump-Russia scandal and cover-up Trump putting himself above the law is a threat to our democracy, and we’ve got to get Congress to stop him," the organizers said in a post online about the event. "We're mobilizing immediately to demand accountability, because Trump is not above the law."

Contributing: Associated Press