The home of a prominent Israeli peace activist has been vandalised, with death threats and swastikas spray-painted on walls and a nearby vehicle, amid alarm among human rights groups about increasingly hostile and violent actions against them.

Police confirmed they were investigating the attack on the Jerusalem home of Hagit Ofran, who works for Peace Now, an Israeli organisation that monitors settlement activity in the West Bank and East Jerusalem.

The graffiti included the words "Hagit Ofran ‚Ä" zal [of blessed memory]"; "Rabin is waiting for you", a reference to the assassinated Israeli prime minister Yitzhak Rabin; and "price tag", the signature of extremist settlers who carry out operations in revenge for moves to demolish unauthorised West Bank outposts. The names of two recently dismantled outposts were also sprayed on walls.

It is the second such attack on Ofran's home in two months. On Sunday, Peace Now's offices were evacuated after a telephone call warned of an imminent bomb attack. "The building will explode in five minutes," the caller said. Staff found the words "price tag" had been sprayed on the building.

"We are looking at who could be behind this action," police spokesman Micky Rosenfeld said on Tuesday. Extremist settlers were among the suspects, he added.

Ofran said the perpetrators were trying to intimidate activists. "The discourse in Israel has become truly dangerous," she told Haaretz newspaper.

In a statement, Peace Now said: "The responsibility for price tag attacks is [prime minister Binyamin] Netanyahu's. The incitement and the harsh words of the coalition members in favour of illegal outposts and against the justice system and leftwing organisations is seeping into the ground and giving support to the price tag vandals."

The attack came as Netanyahu announced he was supporting two parliamentary bills to curtail the foreign funding of Israeli human rights organisations. Groups targeted by the bills have said the legislative move is an attempt to silence them and restrict their work.

A human rights worker who asked not to be named said: "There is a public atmosphere of trying to stop human rights activity. You see it in the Knesset [Israeli parliament] in these bills and statements from politicians who claim these organisations are actually helping terror."