The march presented the Kremlin with a quandary: either use force to break up the protest, and risk provoking more anger, or stand aside and let the protest take place, which risked revealing weakness to the Kremlin's opponents. Instead he will be held under house arrest for two months while he is investigated.
Mr Golunov, 36, is a freelance journalist who had been working for the Latvia-based news website Meduza, among others.
Russia's interior minister says all charges against a prominent investigative journalist arrested on suspicion of drug dealing have been dropped.
On Monday, three top newspapers Kommersant, Vedomosti and RBK published the same front page with the words "I am/we are Ivan Golunov" in giant letters - a bold act of defiance in a country where most media toes the Kremlin line. "Similar cases here have previously got caught up in Russia's legal system with no way to get out, with the Kremlin saying they were unable to free a detained person - and Golunov's supporters were very anxious he would meet the same fate".More news: Oil price could fall to $30: Novak
"Together, we made the unbelievable happen: we stopped the criminal prosecution of an innocent man. Thank you!" the statement said.
A planned central Moscow protest - which did not receive permission from state officials - will still go ahead tomorrow, Vaessen said, with organisers promising "not to rest" until those who organised Golunov's detention are brought to justice.
Those who spoke out against Golunov's detention included the Committee to Protect Journalists, which noted Russia's "long history of politically motivated allegations against reporters".
In Canada, Foreign Affairs Minister Chrystia Freeland told reporters, "We are following the current situation in Russian Federation very closely and with great interest and attention". The case is also being closely watched by the Kremlin, the president's spokesperson Dmitry Peskov said on Monday, adding that there are "questions that need to be clarified".More news: Best picks for Bangladesh vs Sri Lanka in Cricket World Cup today
Kremlin critics say the few opposition and independent media that still operate in Russian Federation are under huge pressure, with their journalists frequently facing criminal probes, physical attacks and official pressure.
"This is a test for us all", NTV channel host Irada Zeinalova said onscreen.
The police say that they found drugs inside the journalist's backpack, which he allegedly wanted to sell, and later found some more in his apartment.
His lawyer said he was beaten, suffering bruises, cuts, a concussion, and a broken rib during or after his arrest.More news: Kawhi Leonard sues Nike over 'Klaw' logo ownership
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