The wife of Alexander Litvinenko has told Sky News she is devastated she cannot return to Russia to see her family over fears for her safety.
Marina Litvinenko told Kay Burley she has not been back to her home country for 18 years and now is unable to see her mother face-to-face.
She fears that if she goes to Moscow she will be put in prison - or worse - and would never again see her UK-based son Anatoly, 33.
Her husband, a former Russian spy, died after being given radioactive polonium in tea in a hotel in 2006, and several friends of the couple, including Boris Berezovsky and Nikolay Glushkov, have also died in mysterious circumstances.
Her comments also come after the British government blamed the Russian state for poisoning another ex-spy, Sergei Skripal, and his daughter Yulia in Salisbury, using a nerve agent.
Mrs Litvinenko, tears welling in her eyes, said: "Every time I think about going, something happens, like what happened with Sergei Skripal, what happened to Nikolai Glushkov, or sometimes what happened inside of Russia, when innocent people are put in prison for posting on their Facebook.
"Sometimes I think that nothing will happen to me and when I come to Russia I will be so sad because I wasted my time - I could not see my mum for a long time, I couldn't go the funeral of my father.
"You know it's very difficult to understand what is right to do and what is not, because it's all about people who I love and who I want to see.
"But I have my son here and I don't think he would behave if something happened to me in Russia. I just try to keep a balance of what I need to do."
She says she is no longer able to see her mother, who used to travel to the UK, because she is too fragile to leave Russia since the death of her father.
Her mother regularly implores her daughter not to be controversial and not to "say something illegal (in Russia)", so Mrs Litvinenko will be safe to go to Moscow to see her.
Despite claims by British Foreign Secretary Boris Johnson that Vladimir Putin was "overwhelmingly likely" to have ordered the attack on Mr Skripal and his daughter, Mrs Litvinenko was reluctant to lay the blame entirely at the Russian President's door.
She said he is a "mouthpiece" for the "special people" at the top of Russian politics and society, uniting several "absolutely different groups", and was now a "slave to (the) system" who does not live an "easy life".
"This man represents the special people around him; it's not just about Mr Putin. It's more about representation of people who support him and his way," she said.
"He couldn't do anything himself, without this support. We know he represents the military - people from military office; people from security office; and some people from intelligence service office.
"He needs to deliver everything that these people want."
Mr Putin's re-election for another six years did not surprise her, she said, as the atmosphere inside Russia is the same as in the era of Josef Stalin - the brutal dictator who repressed the country for decades and is said to be responsible for the deaths of millions.
"When... people support Putin, (and) go… and vote for him, I… remember what happened to Russian people during Stalin era.
"It's the same. They believed this guy. They believed he was the father of Russia. He (Stalin) killed so many people and life was so tough.
"And it makes me feel very nervous... because, when it was the Breshnev era, in the 70s, people were very cynical. They understood.
"But today, some of them are not cynical. They really believe Putin wants to protect them from (the) West and the West wants to destroy Russia."
She said she would not be surprised if Mr Putin - who has already been President for 18 years - tries to change Russia's constitution to allow him to remain in the post potentially permanently, in a similar way to a change enacted by China's leader Xi Jinping, who has abolished a limit on terms in power.
Mrs Litvinenko said what was required in response to the poisonings of Mr Skripal and his daughter was for the British government to be "strong".
She said the only course of action was punitive personal sanctions against people who have benefited from the way Russia has been run since the 1990s and who spend their wealth in Britain and Europe.
"When you talk about what are the better things to do, it's all about money," she said.
"If you want to punish these people, make it not possible that they spend their money here, in Europe; not to accept their money in business.
"I'm not talking about all Russia, I'm talking about certain people. They have to be very personal sanctions.
"Some people from the military or the security service, you could say they are already not travelling to the UK or to Europe, but the members of their family, they have everything here."