YAROSLAVL, Russia — A 45-year-old Russian accountant and relative of the two Russians poisoned in a nerve agent attack in Britain last month said in an interview late Thursday that she was “scared” for them, calling the British authorities untrustworthy and casting doubt on their version of events.

In the interview in Yaroslavl, Russia, where she lives with her husband and her two children, the accountant, Viktoria Skripal, who has been thrust into an escalating confrontation between Russia and the West, also said that she doubted that Britain would grant her a visa that would allow her to see her relatives.

The relatives, Sergei V. Skripal, a former Russian spy, and his daughter, Yulia, have been hospitalized in Salisbury, England, since the attack on March 4. Ms. Skripal’s suspicions, which echo the accusations of Russian officials, have become the country’s latest riposte to British assertions that Moscow was responsible for the attack carried out with a rare class of military-grade nerve agents developed by the Soviet Union called Novichoks.

“Wouldn’t you be scared?” she said. “While I don’t know the whole situation, they ask me to voice my opinion,” she said of the British authorities, who she said wanted her to denounce Russia. “If they tell me, ‘We’ll return Yulia to you if you say ‘Russia is filth,’ then I’ll stand up and say ‘Russia is filth’ and take Yulia back to that filth.”