Progressive groups are organizing some 140,000 protesters to hit the streets nationwide within hours with massive demonstrations if President Donald Trump decides to fire special counsel Robert Mueller, The Washington Post has reported.

Although the White House has repeatedly insisted that Trump has no intention of dismissing Mueller, activists on the left are wary of the president’s plans and say they fear he could act when Congress and the public are distracted.

In anticipation of such a move, more than two dozen progressive groups have spent the past several weeks registering more than 140,000 people who have pledged to begin protesting within hours of Trump’s decision, at set locations in more than 600 cities.

"The reaction will be swift," Lisa Gilbert, vice president of legislative affairs for Public Citizen, an environmental and government reform organization promised the Post, adding that the willingness of people to sign up for such an action "shows the energy and passion out there" to resist Trump.

The threats of mass protests appear also to have broad support within the Democratic Party and planning for such a massive response is helping to unite the activist left amid recent divisions over what the most effective way is to show their disgust with Trump and his policies, according to the Post.

Fearing a backlash from the public, even a number of Republican lawmakers have warned that Trump should not fire Mueller and must allow him to continue his investigation into Russian election meddling, The Hill reported.

One example of the preparation that the leftist groups have already undertaken is that organizers in New York already have stockpiled bullhorns in apartments near Times Square for the New York City demonstration, the Los Angeles Times reported.

But some scholars warn that even with such planning the demonstrations could disappoint due to protest fatigue.

"The potential firing of Mueller would be outrageous, but we have already seen so many outrageous things," Purdue University sociology Prof. Rachel Einwohner told the Post. “I don’t know this one would create any more resistance and outcry than what we’ve already seen."