By Agence France-Presse
"The British ambassador will be summoned to the Russian foreign ministry on Saturday," TASS state news agency said, quoting the foreign ministry.
TASS said Moscow was expected to inform Bristow about retaliatory measures after Britain's decision to expel Russian diplomats over the poisoning of former Russian double agent Sergei Skripal and his daughter.
The British embassy did not give a time when Bristow was to present himself at the ministry but said he would leave "shortly".
On Friday evening, foreign ministry spokeswoman Maria Zakharova told TASS that "the Russian side has taken all the decisions and they will be shortly communicated both to the British side and to the public."
Bristow had also been summoned on Tuesday as a bitter row over the poisoning of a former double agent gathered pace.