Spyware from the Israeli hacker-for-hire company NSO Group was found on the phones of six Palestinian rights workers, Amnesty International and internet security activist group Citizen Lab said on Monday.

The announcement followed investigations carried out by international rights group Front Line Defenders who took their findings to Amnesty and Citizen Lab for confirmation.

Three of the six individuals who were targeted belonged to Palestinian rights groups that were labeled, in a heavily criticized move, as terrorist organizations by Israel last month.

NSO was recently blacklisted by the US Commerce Department after its technology was found on the devices of journalists, rights activists and lawmakers around the world.

Who was hacked?

The three of the hacking victims who agreed to be named were Ubai Aboudi — who is a US citizen — from the Bisan Center for Research and Development, Ghassan Halaika from the Al-Haq rights group, and Salah Hammouri of the human rights organization Addameer.

All three were banned after being designated as terrorist organizations on October 22 by Israeli Defense Minister Benny Gantz.

Israel has yet to publicly provide evidence for the accusation and has been criticized for what some see as an attempt to silence criticism.

Four of the hacked phones used Israeli SIM cards. NSO has claimed that exported versions of the software cannot be used to hack Israeli devices.

Who did the hacking?

It is not yet clear who put the spyware on the phones of the six Palestinians, or if other phones may have been hacked.

The NSO Group said in a statement that it does not identify its customers for contractual and national security reasons. It has previously said that it only sells its software to government agencies. However, heavy criticism has been leveled against the company and the Israeli government for the abuse carried out and the lack of oversight.

"The exposure of illegal spying on peaceful Palestinian human rights defenders, coming on top of baseless claims about terrorism against internationally respected human rights organizations emphasizes how important is the continued support of the international community for their legitimate work," Front Line Defenders executive director Andrew Anderson said.

He went on to call for "renew[ed] efforts to rein in the use of spyware against human rights defenders, journalists and other civil society activists."

Tehilla Schwartz Altshuler from the Israel Democracy Institute called the findings "disturbing." She told The Associated Press that if it is proven that the Israeli government was involved, then it "actually complicates the relationship of the government with the NSO," as that would make Tel Aviv both secretly a client and a regulator.

The Israeli Defence Ministry did not immediately comment on the findings. 

ab/rt (AP, Reuters)