JERUSALEM — A pipe bomb exploded today outside the home of a prominent Israeli scholar and outspoken critic of Jewish West Bank settlements, lightly wounding him in what police suspect was an attack by Jewish extremists.

Investigators found posters in Professor Zeev Sternhell’s neighborhood offering a $320,000 prize to anyone who kills a member of Peace Now, a dovish Israeli group whose views Mr. Sternhell shares.

If extremists were behind the attack, it would be one of the worst instances of political violence inside Israel since an opponent of peace negotiations with the Palestinian Arabs murdered Prime Minister Yitzhak Rabin in 1995.

Human rights groups say settlers have been increasingly using violence against Palestinian Arabs and Israeli soldiers, in what appears to be an attempt to deter Israeli authorities from making any attempt to evacuate settlements.

The settlement movement fervently opposes the peace talks and rejects the territorial withdrawal a deal would require.

A person close to Mr. Sternhell’s family said, without elaborating, that the professor had received threats in the past. She spoke on condition of anonymity because of the incident’s political sensitivity.

The bomb was planted on the doorstep of Sternhell’s home in a quiet Jerusalem neighborhood, exploding when he opened the door, a Jerusalem police spokesman, Shmuel Ben-Ruby, said. The assailants were not apprehended.

Sternhell had minor shrapnel wounds in one leg and will remain hospitalized at least until Friday, authorities said.

An internationally known scholar on fascism and a Holocaust survivor, he was awarded the country’s highest honor, the Israel Prize, this year. The award drew criticism from settlers and their supporters.

A national police spokesman, Micky Rosenfeld, said investigators believe the attack was ideological.

An activist with a fringe settler group calling itself the National Jewish Front, Itamar Ben-Gvir, said “I don’t denounce this incident, but say categorically that we are not involved.”

In a statement, Peace Now identified Mr. Sternhell as a “veteran supporter” and said Israeli authorities shared responsibility for the attack for not cracking down on settler violence in the West Bank.

Peace Now’s head said he was placed under police protection after the attack, but Mr. Rosenfeld could not confirm that.

The attack drew condemnation from Israeli politicians, including some from hard-line parties.

Prime Minister-designate Tzipi Livni said in a statement that Israel could not gloss over the attack, which she described as “intolerable.”

“It’s the responsibility of the state and its people to denounce these events before they occur,” Ms. Livni said.

Settlers regularly clash with Palestinian Arabs and Israeli peace activists in the West Bank, but the use of weapons against political opponents in Israel is uncommon.

There have, however, been precedents. A pro-settlement extremist shot and killed Mr. Rabin, who was spearheading efforts to strike a peace deal. Another extremist killed a member of Peace Now with a grenade at a 1983 peace protest.