This photo taken on March 17, 2018 shows the British Consulate General in St. Petersburg, Russia. (Xinhua/AP)

MOSCOW, Dec. 28 (Xinhua) -- Russia and Britain have reached in principle an agreement to gradually restore diplomatic staff starting January, Russian Ambassador to London Alexander Yakovenko said Friday.

"I'm not sure that we will manage to restore all employee numbers, but at least half of the embassy will be there," Yakovenko said in an interview with the Russia 24 TV channel.

In March, Britain expelled 23 Russian diplomats over Russia's alleged role in poisoning former Russian agent Sergei Skrip in the British city of Salisbury earlier in the same month.

More than two dozens of countries, including the United States, announced the expulsion of Russian diplomats as a sign of solidarity with Britain.

Russia denied involvement in the poisoning case and expelled an equal number of foreign diplomats in response.