The protesters were detained in Minsk, the capital, Wednesday during an unsanctioned rally over Belarus' economic policies, which have led to a currency crisis, RIA Novosti reported.
Belarusian President Alexander Lukashenko has denied human rights are being violated and he told his countrymen the West is "trying to bend us."
"I am certain that we will not be attacked because they are afraid of us," Lukashenko said at the Brest Fortress during a ceremony commemorating the 70th anniversary of the start of the Great Patriotic War of 1941-1945.
The journalists detained Wednesday were released, but a Russian human rights activist said Russia can't ignore the brutal treatment of opposition protests in Belarus.
"Russia must certainly interfere as human rights violations cannot be just a domestic matter, it is a subject of concern for the entire global community," said Ludmila Alekseyeva, the head of the Moscow Helsinki Group.
Former U.S. Secretary of State Condoleezza Rice has called the 56-year-old Lukashenko "the last dictator of Europe."
"This is why Russia should be the first one to react to what the Belarusian authorities are doing," Alekseyeva said.