JERUSALEM (AP) – Unknown assailants hurled a pipe bomb early Thursday at an internationally known Israeli scholar who advocates peace with the Palestinians and opposes the Jewish settlement movement, lightly wounding him, police said.

Police suspect hardline Israeli extremists targeted Professor Zeev Sternhell because of his political views, police spokesman Micky Rosenfeld said. Investigators found posters in Sternhell’s neighborhood offering a prize 1.1 of million shekels ($320,000) to anyone who kills a member of Peace Now, a dovish Israeli group.

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 murdered Prime Minister Yitzhak Rabin in 1995.

Several assailants were waiting for Sternhell shortly after midnight Wednesday when he exited his home in a quiet Jerusalem neighborhood and went to close the courtyard gate, Rosenfeld said. They escaped after throwing the small bomb, he said.

Sternhell had minor shrapnel wounds in one leg and will remain hospitalized at least until Friday, said Shoham Ruvio, a spokeswoman for Shaare Zedek Medical Center.

Sternhell is best known for his work on the history of fascism. A Holocaust survivor who moved to Israel as a teenager, he was awarded the country’s highest honor, the Israel Prize, earlier this year. The award drew fire from settlers and their supporters, and some unsuccessfully petitioned the Supreme Court to try to block the prize. Rosenfeld said detectives were investigating the attack.

“We believe the background is ideological,” he said.

Settlers regularly clash with Palestinians 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 Rabin in 1995 as Rabin spearheaded efforts to strike a peace deal with the Palestinians. Another extremist killed a member of the Peace Now movement with a grenade at a peace protest in 1983.

Human rights groups say West Bank settlers have been increasingly using violence against Palestinians 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 Israel has been holding with the Palestinians and rejects the territorial withdrawal an agreement would require.

Yariv Oppenheimer, who heads Peace Now, said he was placed under police protection after the attack on Sternhell.

“In the past year we’ve felt that extremism on the other side is mounting, as are the hatred and the boldness,” he told Army Radio. Rosenfeld could not confirm that police were guarding the Peace Now leader.

The attack drew condemnation from Israeli politicians, including some from hard-line parties. Lawmaker Zevulun Orlev of the National Union Party, which is affiliated with the settlement movement, called it “a terrible deed.” “We can hold a civilized dialogue that is more moderate and balanced, in order to dissipate the tensions in Israeli society,” Orlev told Army Radio.