The RIA Novosti correspondent, who had been accredited by the Belarusian Foreign Ministry, said they were attempting to cover an unsanctioned rally near Minsk's Partizanskiy Prospekt. Communication with the reporter was lost when protesters began to scatter as security forces moved in.
After some time, the reporter said that she had been detained and transferred to a police station in Minsk's Zavodskoy region before being eventually freed.
The other detained reporter was a correspondent from Russia's Interfax agency, the correspondent said.
On 30 November, a RIA Novosti correspondent was detained while attempting to cover the same day's pensioners' protest in the Belarusian capital.
The Belarusian opposition has staged regular unsanctioned protests on weekends following the 9 August presidential election, which saw incumbent Alexander Lukashenko emerge victorious.