WESTWOOD, Mass.--Andrei Sakharov, the Nobel Peace Prize-winning physicist who became a symbol of Soviet dissidence, died yesterday, his relatives reported. He was 68.

Sakharov, a human rights leader who later was elected to the Soviet Parliament formed under President Mikhail Gorbachev and became one of its leading voices, died in Moscow, relatives said.

Liza Semyonov, 34, the daughter-in-law of Sakharov's wife, Yelena Bonner, said Bonner called about 6 p.m. yesterday to notify the family of Sakharov's death.

Attempts to reach Sakharov's home in Moscow by telephone were unsuccessful. Sakharov had suffered from angina, but during a visit to the United States in December 1988, doctors at Massachusetts General Hospital determined he did not need heart surgery or a pacemaker after cardiovascular tests.

Sakharov was a top Soviet physicist and helped developed its hydrogen bomb in the 1950s, but became a dissident leader in the 1970s.

Sakharov's clashes with four Kremlin leaderships over human rights, foreign policy and the morality of the nuclear weaponry he helped develop as a physicist sent him into forced exile in the Soviet city of Gorky, about 250 miles from Moscow, in 1980.

He was recalled in 1986 by Gorbachev, and swiftly took a leading role in urging the Soviet leader to follow through on Gorbachev's twin policies of perestroika, or restructuring, and glasnost, or openness.

His activism continued almost until his death. On Tuesday, he engaged in an angry exchange with Gorbachev in the Parliament over the party's monopoly on political power.

His campaigns on behalf of disarmament and human rights won him the 1975 Nobel Peace Prize, and he steadfastly argued that without international respect for human rights there could be no guarantee of peace.

White House spokesperson Roman Popadiuk read a statement praising Sakharov as "a historical figure who will be long remembered for his human rights efforts in the Soviet Union. His voice was an important dimension in the contemporary changes under way in Soviet society."