Skripal, who was poisoned along with her ex-spy father Sergei in a nerve agent attack, said Wednesday her recovery has been "slow and painful" and that she doesn't need assistance offered by the Russian Embassy.

President Vladimir Putin's spokesman, Dmitry Peskov, said the Kremlin doesn't know whether Skripal made her statement under pressure or independently, where she is or if her rights have been respected by British authorities.

Russia has vehemently denied any involvement in the March 4 poisoning in the English city of Salisbury and blamed Britain for staging it.

Peskov described the Skripals' poisoning as an "unprecedented international provocation."

"We have every reason not to trust it," he said of Skripal's statement in a call with reporters.

The Russian Embassy in London went a step further, tweeting: "The bottom line is that MI5 should expect better results from their translators - for 32K/year (STG32,000 a year) they should be able to write statements which sound more Russian."

The tweet echoed statements by many commentators in Moscow, who said the wording of Skripal's remarks sounded odd and artificial.

The cousin of Yulia Skripal said on Russian state television late Wednesday that she appeared to be delivering a statement written by others.

"The text is learned by heart - I mean she doesn't speak emotionally, she says it very quickly," Viktoria Skripal said.

Australian Associated Press