JERUSALEM, April 17 (Xinhua) -- Palestinian cars were vandalized and racist slogans were spraypainted on them in northern West Bank early Tuesday, in a suspected hate crime by Israeli extremists, Israeli police said.

The police suspected that the attack in the Palestinian villages of Lubban ash-Sharqiya and as-Sawiya, south of Nablus, was perpetrated by ultra-nationalist Israelis.

A police spokesperson said that the perpetrators punched the tires of cars early in the morning and sprayed graffiti related to "the Nahlieli Underground," a group of Israeli settler youths suspected of other attacks against Palestinians.

The slogans included "Expel or Kill" and "Price Tag," referring to attacks by far-right Israelis against Palestinians and their properties.

According to the police, an investigation was launched but they have yet apprehended any suspects.

On Thursday, in the village of Aqraba, also in the Nablus area, a door of a mosque was torched and hate slogans were sprayed on its walls, including "Revenge" and "Price Tag."

Two weeks ago, five vehicles and walls were vandalized in the village of Farata in the Nablus district.

In a statement in the wake of the attack, Yesh Din, an Israeli human rights group, urged Israeli law enforcement authorities to take a firm action against the attacks.

"These attacks... are intended to harm and frighten Palestinians in their homes, and to defy the law enforcement authorities. They must be dealt with severely before the criminals escalate and harm human life," the group wrote in a post on its Facebook page.

Far-right Israelis have carried out thousands of so-called "price tag" attacks over the past years.

The attacks included violence against Palestinians in the West Bank and Israel, and vandalism of mosques, churches, cemeteries, and personal property. Most of the incidents remain unsolved as the law enforcement authorities usually fail to arrest and charge any suspects.