Moscow has told Britain it must cut "just over 50" more of its diplomatic and technical staff in Russia as the crisis escalated over the nerve agent attack on former spy Sergei Skripal. More than 100 Russian diplomats have been expelled by various countries, including 23 from Britain itself, to punish the Kremlin over the March 4 attack on Skripal and his daughter Yulia in the historic English city of Salisbury. London says Moscow was responsible for poisoning the Skripals. Russia flatly denies that. Russia had already retaliated in kind by ejecting 23 British diplomats. On Friday, the Foreign Ministry summoned British Ambassador Laurie Bristow and told him London had one month to further cut its diplomatic contingent in Russia to the same size as the Russian mission in Britain. It also expelled 59 diplomats from 23 other countries for backing Britain. A spokeswoman for Britains foreign ministry called the Russian move regrettable, and said it was considering the implications of the measures. It did not say how many diplomatic staff in Russia would be affected, while the British Embassy in Moscow says it does not make staff numbers public. Russian Foreign Ministry Spokeswoman Maria Zakharova told Reuters the demand meant Britain would have to cut "a little over 50" more of its diplomatic and technical staff in Russia on top of the 23 diplomats who have already gone home. "We asked for parity. The Brits have 50 diplomats more than the Russians," Zakharova said on Saturday. When asked if that meant London would now have to cut exactly 50 diplomatic and technical staff, she said: "A little over 50." Meanwhile, Britain said it was considering Moscows request for consular access to Yulia Skripal, while taking into account her wishes. The 33-year-old came out of critical care on Thursday and was "improving rapidly", said Salisbury District Hospital. She is now in a "stable" condition -- with the BBC reporting that she was conscious and talking. Sergei Skripal, 66, remains in a critical but stable condition.