Cabinet minister Natan Sharansky (search), a frequent critic of Israel's (search) peace moves with the Palestinians, submitted his resignation Monday in protest over the planned withdrawal from the Gaza Strip (search).

Sharansky, a former Soviet dissident whose imprisonment there made him a hero to world Jewry, wrote in a letter to Prime Minister Ariel Sharon that he opposes making unilateral concessions to the Palestinians.

Sharansky, the author of "The Case for Democracy," a political study endorsed by President Bush, also wrote that any progress in peace talks should be linked to greater democracy in the Palestinian areas.

Cabinet Secretary Israel Maimon confirmed that Sharon's office received Sharansky's letter Monday morning and that the resignation would take effect on Wednesday.

Sharansky was minister for Diaspora Affairs and Jerusalem.

In a decade in Israeli politics, he had criticized successive governments for their handling of negotiations with the Palestinians, arguing that too many concessions were being made with too little in return. Since Sharon announced a year ago that he wants to withdraw from Gaza and parts of the West Bank, several Cabinet ministers have been fired or have quit in protest.

Sharansky started out in Israeli politics as leader of Israel B'Aliya, a party largely supported by immigrants from the former Soviet Union.

As one of the Soviet Union's best-known political prisoners, Sharansky fought for the right for Jews to emigrate to Israel and was jailed in 1977 on charges of spying for the United States.

He spent 10 years in Soviet prisons before strong international pressure forced the Soviet government to strip him of Soviet citizenship and deport him. He immigrated to Israel in the mid-1980s.