JERUSALEM - Suspected Jewish extremists fired a pair of tear gas canisters into the home of a Palestinian family in the West Bank early Tuesday and sprawled the word "revenge" in Hebrew on the house, Israeli police said.

The family was asleep and unharmed in attack, said police spokeswoman Luba Samri, adding that an investigation was underway.

For years, Jewish extremists have vandalized or set fire to Palestinian property, as well as mosques, churches, the offices of dovish Israeli groups, and even Israeli military bases. The so-called "price tag" attacks seek to exact a cost for Israeli steps seen as favoring the Palestinians.

Prime Minister Benjamin Netanyahu has pledged "zero tolerance" for such attacks, and Israel has authorized a series of steps, including administrative detention, to help stamp out the trend.

"There is Arab terrorism that we deal with and combat day and night in every arena, but unfortunately, from time to time, there are also acts of terror committed by Jews," Netanyahu said Tuesday. "We will not accept terror from any side."

Tuesday's attack in a village near Ramallah comes as Israel says it has made significant progress in the investigation of the most notorious of these attacks, a July firebombing that killed a Palestinian toddler and his parents in Duma. That attack prompted widespread condemnation and pledges by Israel's government to get tougher on Jewish vigilantes. Even with the stepped-up measures, Israel has been unable to charge those responsible for the deadly attack.

In recent weeks, anger has been rising among far-right activists who object to the arrests and interrogation of the suspected attackers. Some have claimed that Israel's Shin Bet security service has tortured them to exact a confession for an attack that was deeply embarrassing for Israel.

In Tuesday's attack, in addition to the word "revenge," the graffiti said "regards from the detainees of Zion" - a possible reference to those who have been arrested as suspects.