Former Soviet dissident Yelena Bonner has died in the United States at the age of 88.

Bonner, the widow of Nobel Peace Prize laureate Andrei Sakharov, died Saturday in a Boston hospital after undergoing heart surgery for a third time, according to AFP.

Born in Turkmenistan to Jewish revolutionaries, Bonner exposed rights abuses in Chechnya. She served as the only link between the West and her internationally known nuclear physicist husband, a human rights activist who in the 1980s was sent to internal exile in the city of Gorky, a closed city inaccessible to foreign observers. In 1975, Bonner accepted the Nobel Peace Prize on Sakharov's behalf in Oslo, Norway.

She will be laid to rest next to her husband in Moscow's Vostryakovo cemetery, her daughter said in a statement to the media.

A pediatrician by training, Bonner spent much of her life in the Soviet Union's civil and human rights movement. However, she spent her last few years in the United States, having become disillusioned with the direction taken by “liberated” Russia.

Two years ago, she delivered a particularly strong pro-Israel speech in Oslo, blasting the Quartet of peacekeeping nations and opposing the so-called "two-state solution" that would create a new Arab country from the Palestinian Authority. She also wrote an open letter to her human rights colleagues, demanding to know why the fate of kidnapped IDF soldier Gilad Shalit did not seem to trouble the world in the same way as the rights of prisoners held in Guantanamo Bay.

Although Russian Human Rights Commissioner Vladimir Lukin said in a statement that Bonner had made some “harsh pronouncements” in her 40 years as an activist, he acknowledged that “only people like that could help us cross from an old era into a new one.”

Natan (Anatoly) Sharansky, former Prisoner of Zion [term for Jews imprisoned for wanting to make aliyah during the years of Communist rule in Russia] and today head of the Jewish Agency, said in his statement: "The Jewish world and the state of Israel lost a stalwart and valiant defender today. The international community of human rights activists, supporters of democracy, dissidents and political prisoners lost one of their most important leaders. While Andrei Sakharov was the heart of the movement to defeat the evils in the Soviet system, Yelena Bonner was the catalyst who led us to action.

"On a personal note, my family and I feel that we have lost a dear friend, one who stood by us and did not leave our side even when we stood at the gates of Hell. Her cherished memory will remain in my heart forever."