By Stefan J. Bos
Armed with flags and slogans protesters expressed their appreciation for the ruling Social Democratic Party at a time of corruption allegations against high ranking politicians and officials.
The party bussed in supporters from around the country for the rally, while others made it on their own.
The crowd claimed that prosecutors have too much power and allegedly tapped phones illegally and unjustly targeted officials.
Several participants said prosecutors use the same tactics as during Romania's more than four decades of communist rule.
The Social Democratic Party's deputy Liviu Plesoianu, who wants to become the country's next president, said
Romanians wish to live in freedom. "We have gathered here, hundreds of thousands of free Romanians, to protest against the deep state who took..our country hostage for more than a decade," he said.
"We are here to protest against the secret protocols between the secret services and the prosecutors, between the secret service and the judicial system. We are here to protest against the illegal mass interception and surveillance of millions of Romanians. We are here to protest against a hideous experiment, the experiment of a fake anti-corruption fight," the politician added.
But critics said the rally was designed to intimidate judges and Romanian President Klaus Iohannis, who supports the anti-corruption fight.
President Iohannis opposes government attempts to fire the country's chief anti-corruption prosecutor, who is widely respected in Romania and by the European Union.
The office of the anti-corruption prosecutor successfully prosecuted 713 officials in 2016, including some 28 mayors and a senator. Last year, Romania had its biggest protests since communism ended after the government tried to decriminalize official misconduct.
Despite these efforts, experts say that Romania remains one of the EU's most corrupt nations.