JERUSALEM – A new rogue element has emerged in the Israeli-Palestinian gallery: Unknown assailants, widely assumed to be Jewish extremists, have vandalized Muslim cemeteries, mosques and farmlands in a spate of attacks that have put the country on edge.

These attacks, which in recent days have spread from the West Bank into Israel proper, have stoked fears of heightened violence and sparkedcalls to find and punish the assailants. On Sunday, Israeli leaders chimed in with condemnations, and police said they were stepping up efforts to halt the violence.

“It’s against everything that the Jewish people stand for, as a country and as a democracy,” said President Shimon Peres, a Nobel peace laureate. “I am sure that our police will apprehend all the people who did this, the criminals, and we shall not let them walk free.”

In the latest incident, vandals sprayed-painted “Death to the Arabs” in Muslim and Christian cemeteries in the Jaffa section of Tel Aviv. The rampage, discovered late Saturday after Yom Kippur, the holiest day in the Jewish calendar, followed a mosque burning last week in an Arab village in northern Israel. The torching set off violent clashes between residents and police in a town that has historically been a model of coexistence.

The two incidents were among the first to take place inside Israel, where Arab residents, in contrast with their Palestinian brethren in the neighboring West Bank, are citizens.

For several years, Israeli settlers have frequently attacked Palestinian targets in the West Bank, vandalizing mosques and uprooting olive trees.

These attacks are meant to protest Israeli government policies seen as sympathetic to the Palestinians, who hope to make the West Bank part of an independent state. Nationalist settlers oppose a Palestinian state on what they say is land promised to the Jews in the Bible.

On Sunday, some 100 settlers attacked a group of Palestinian villagers in their olive groves near Nablus in the northern West Bank with sticks and stones, witnesses said. The army said it rushed to the scene and broke up the clash, allowing the farmers to harvest their crop.